Luận văn effect of zr and la based co doping on electrical properties of lead free barium titanate batio3 thin films

Dependence of volumetric energy-storage density ae os recoverable energy-slorage đensity 17.„„, and cnergy-storage efficiency 17 on applied electric field or BZ.T thin fibns with various

TLANOI UNIVERSITY OF SCIENCE AND TECIINOLOGY

MASTER’S THESIS

Effect of Zr and La based co-doping on electrical properties of lead-free barium

titanate BaTiO; thin films

TRAN THI DOAN Doan.‘t'l202748M @sis.hust.eduyn

Major: Materials Science

Supervisor: Prof Vu Ngoc [lung

Department: Micro-Blectro-Mechanical-System Laboratory

Tnstitute: International Training Institute for Materials Science

HANOI, 05/2022

HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY

MASTER’S THESIS

Effect of Zr and La based co-doping on electrical properties of lead-free barium

titanate BaTiO; thin films

TRAN THI DOAN Doan TT202748M @sis.husteduyn

Major: Material Science

Supervisor (Sign and write fall name)

HANOI - 05/2022

Acknowledgment

Fustly, I would like to cxpress my deepest appreciation to my supervisor,

Prof, Vu Ngoc Hung, who direcfly instructed me throughout this tescarch project

I am also grateful to Dr Nguyen Duc Minh of MDSA+ Institute for

Nanotechnology at University of ‘Iwente, Netherlands { am extremely thankful

and indebled to him for sharing his expertise as well aa the valuable guidance and encouragement extended to me

T would like to extend my sincers thanks lo MSc Dang Thi Ha, Dr Vu Thu,

Lien, Dr Ngo Due Quan, and all of members in MUMS laboratory for their

enthusiasm to help me through the process of research

Ltake this opportunity to express gratitude to all professors, lecturers, and

employees al TTTIMS for their kindness to support me durmg a period T have

already studied and worked there

Finally T want to give special thanks to my family for providing me with

their unfailing support and encouragement during my years of study and

research

Abstract

BaTliO;-based materials with a perovskite structure have attracted mterest

because some of them are potentially valuable materials due lo their

environment-(riendly properties In this study, lead-free Ba(79 25Tip.7)05 (BZT)

and La-doped Ba(Z1925'ip 75)03 (BLZ‘L) thin films were grown on Pt/l'i/Si0,/Si

substrates via a sol-gel spin-coating method

‘The effects of various annealing temperatures (450 ?00 °C) for BZ thin

Ons on microstructure, dielectric, and energy storage performances were

systematically investigated As XRD result, it was found that the degree of crystallization of the films increased with the increasing amnealing temperature (2) This result indicated a pure polycrystalline perovskite phase of BZT thin

films achieved at 700 °C At the same time, the dielectric constant of the BZT

film also increases as the armealing temperature increases In particular, the

optimal energy-storage density of 30.9 J/cm’ and a large energy-storage

efficioncy of 67.8% could be obtained in the film anncaled at 500 °C, which not

only achieved a large breakdown strength (up to 7000 kV/cm) but also exhibited

a great temperature-dependent energy storage performance stability in a wide

temperature (from 30 °C to 200 °C) a good frequency-dependent energy storage

performance stability in ranging from 100 ta 10000 Hz and an excellent charge-

discharge cycling life with fatigue-free performance up to 10° cycles

Moreover, the effects of La doping of BZT thin films (from 0 — 8 mol.%)

on microstructure, dielectric, and energy storage performances were also

invesligaled As XRD result, if was shown that, La doping enhanced the ability of crystallization of the films with the perovskite B7.T phase achieved at 650 °C

La-doped BZT thin films indicated prominently increasing relaxor behavior with

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

Figure 3.1L Hlectric field dependence of 2,4, and P,, values for La-doped BZ‘

thin films at various La doping contents measured until their corresponding

electric breakdown strength (2p) The data were calculated from the

corresponding #-# LOOPS ccsssscsessssssiesssssseisssssseeseessseeeseesssineeiess + 42

Figure 3.12 Dependence of volumetric energy-storage density (ae os recoverable energy-slorage đensity (17.„„), and cnergy-storage efficiency (17) on

applied electric field (or BZ.T thin fibns with various Ta doping conLents (a) 0%,

(b) 3%, (c) 5%, (d) 8% The data were calculated from the corresponding P-E

Figure 3.13 (a) Energy: storage © densities, recoverable energy-storage and (b)

energy-storage e[liciency were measured at the comresponding gp values, for

BZT thin films with various La doping contents 44

Figure 3.14 (a) Dielectric constant electric field (c-K) curves and (b) dielectric

loss curves of BZT thin films with various doping content, measurement at room

Figure 3.15 The operating-temperature dependence of (a) P-E keop, (©) Pinas Pr

and Py ?,-values for BZ'T thin film at an annealing temperature of 500 °C

The measurements were performed al 4000 kV/em and 1000 Ay 45

Figure 3.16 The operating-lomperalure dependence of (a) cnorgy storage densily (O) and (b) energy storage efficiency (y) for BZT thin film at annealing temperature of 500 °C The measurements were performed at 4000 kV/cm and

Figure 3.17 The Sequencies temperature dependence of of PE ! loops for BAT thin

film at annealing temperature of 500 °C The measurements were performed al

Figure 3.18 The operating-frequencies dependence of @) Pa P, and Prax - Py

values, (b) E, values, (c) energy storage density (U) and (d) energy-storage

efficiency (9) for BZT thin film BZT thin film al anmealing temperature of 500

°C The measurements were performed at 4000 kV/em and room temperature 47

Figure 3.19 a) Comparison of P-E hysteresis loops measured at different

charge-discharge oycles, (b) Pix and P, values as a function of number charge- discharge cveles under an applied electric field of 4000 kV/em and 1 kHz, for the

BAT thin film at annealing temperature of 500 °C The fatigue testing was

performed by applying a tpolar electric field of pulse height 200 KV/em and at

pulse width 100 KLIz (07 5 U8) ccccsssscessseeseesunssseeee sees .49

Figure 3.20 Dependence of (a) energy storage density and q@) energy storage efficiency () on cycling for BZT thin film at an annealing temperature of 500°C

The dala were calculated from the corresponding P-E hysleresis loops performed

at 1000 kVvem, 1 kHz and room temperature - - 49

increasing La-doping concentration In particular, the films with 5 mol.% La-

doping simultaneously exhibit a quite high recoverable energy-storage density

(~7.0 vem") and a large enerpy-storage efficiency (~ 60.7%) under an gp of

1650 kV/em Moreover, dieleewie coustant of La-doped BZT thin films was found to be significantly improved, reaching the wiaximum value of 164 for 3 mol.% La-doped BZT thin film

These results indicated thal lead-free BalZr92sTigz3)O3 and Ta-doped Ba(21/asTia;;)O; thín films were expected to become a candidate materials for

cnergy-storage capacitors

Master student

(Sign and write fall name)

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

1.13 Relaxor ferroelectric coi sean sine Ổ

1.2 Principles for High Energy-Storage in Dielectric Capacitors cece 10

1.2.1 Basic knowledge on dielectric capacitor

Measuring methods of cncrgy-storage deusity for dielectric

11

1.23 Potential dielectrics for high energy-storage application 14

1.3 Overview of barium titanate-based materials - - 15

1.3.2 Liffeels of doping on BaliO; properlie "¬¬

21 Fabrication of BZI and BLZT thin films by sol-gel spin coating

21.1 Overview of sol-gel spin coating method 20

21.2 Fabrication of BZT and BLZT Sols 23

2143 Fabrication of BZT and BLZT thin films 25

2.2 Methods to investigate the structure and properties of BZT and BLZT

3.1.2 — Ferroelectric properties and breakdown strength (Epp) 34

3.1.4 Dieleetrieproperiies Xueesssusoou 38

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Chemical Vapor Deposition

Differential scanning calorimetry

Barium titanate, BaTiO, Barium zirconate titanate, Ba(4r,Ti}O;

Barium lanthanum zirconate titanate, (Ba,La)(Zr.Ti)O;

Pulsed laser deposition

Lead zirconate, PhZrO;

Lead zirconate titanate, Pb(Z1,Ti)O;

Lead lanthanum zirconate titanate, (Pb,La}{(Zr,TijO3

Polar nanoregions

Lead magnesium niobate, Po(Mg,gNbia)Os

Lead zirconate titanate, Pb(Zx,Ti)O3

Relaxor ferroelectric

Thermogravimetric analysis X-Ray diffraction

Figure 3.1L Hlectric field dependence of 2,4, and P,, values for La-doped BZ‘

thin films at various La doping contents measured until their corresponding

electric breakdown strength (2p) The data were calculated from the

corresponding #-# LOOPS ccsssscsessssssiesssssseisssssseeseessseeeseesssineeiess + 42

Figure 3.12 Dependence of volumetric energy-storage density (ae os recoverable energy-slorage đensity (17.„„), and cnergy-storage efficiency (17) on

applied electric field (or BZ.T thin fibns with various Ta doping conLents (a) 0%,

(b) 3%, (c) 5%, (d) 8% The data were calculated from the corresponding P-E

Figure 3.13 (a) Energy: storage © densities, recoverable energy-storage and (b)

energy-storage e[liciency were measured at the comresponding gp values, for

BZT thin films with various La doping contents 44

Figure 3.14 (a) Dielectric constant electric field (c-K) curves and (b) dielectric

loss curves of BZT thin films with various doping content, measurement at room

Figure 3.15 The operating-temperature dependence of (a) P-E keop, (©) Pinas Pr

and Py ?,-values for BZ'T thin film at an annealing temperature of 500 °C

The measurements were performed al 4000 kV/em and 1000 Ay 45

Figure 3.16 The operating-lomperalure dependence of (a) cnorgy storage densily (O) and (b) energy storage efficiency (y) for BZT thin film at annealing temperature of 500 °C The measurements were performed at 4000 kV/cm and

Figure 3.17 The Sequencies temperature dependence of of PE ! loops for BAT thin

film at annealing temperature of 500 °C The measurements were performed al

Figure 3.18 The operating-frequencies dependence of @) Pa P, and Prax - Py

values, (b) E, values, (c) energy storage density (U) and (d) energy-storage

efficiency (9) for BZT thin film BZT thin film al anmealing temperature of 500

°C The measurements were performed at 4000 kV/em and room temperature 47

Figure 3.19 a) Comparison of P-E hysteresis loops measured at different

charge-discharge oycles, (b) Pix and P, values as a function of number charge- discharge cveles under an applied electric field of 4000 kV/em and 1 kHz, for the

BAT thin film at annealing temperature of 500 °C The fatigue testing was

performed by applying a tpolar electric field of pulse height 200 KV/em and at

pulse width 100 KLIz (07 5 U8) ccccsssscessseeseesunssseeee sees .49

Figure 3.20 Dependence of (a) energy storage density and q@) energy storage efficiency () on cycling for BZT thin film at an annealing temperature of 500°C

The dala were calculated from the corresponding P-E hysleresis loops performed

at 1000 kVvem, 1 kHz and room temperature - - 49

increasing La-doping concentration In particular, the films with 5 mol.% La-

doping simultaneously exhibit a quite high recoverable energy-storage density

(~7.0 vem") and a large enerpy-storage efficiency (~ 60.7%) under an gp of

1650 kV/em Moreover, dieleewie coustant of La-doped BZT thin films was found to be significantly improved, reaching the wiaximum value of 164 for 3 mol.% La-doped BZT thin film

These results indicated thal lead-free BalZr92sTigz3)O3 and Ta-doped Ba(21/asTia;;)O; thín films were expected to become a candidate materials for

cnergy-storage capacitors

Master student

(Sign and write fall name)

Chemical Vapor Deposition

Differential scanning calorimetry

Barium titanate, BaTiO, Barium zirconate titanate, Ba(4r,Ti}O;

Barium lanthanum zirconate titanate, (Ba,La)(Zr.Ti)O;

Pulsed laser deposition

Lead zirconate, PhZrO;

Lead zirconate titanate, Pb(Z1,Ti)O;

Lead lanthanum zirconate titanate, (Pb,La}{(Zr,TijO3

Polar nanoregions

Lead magnesium niobate, Po(Mg,gNbia)Os

Lead zirconate titanate, Pb(Zx,Ti)O3

Relaxor ferroelectric

Thermogravimetric analysis X-Ray diffraction

Chemical Vapor Deposition

Differential scanning calorimetry

Barium titanate, BaTiO, Barium zirconate titanate, Ba(4r,Ti}O;

Barium lanthanum zirconate titanate, (Ba,La)(Zr.Ti)O;

Pulsed laser deposition

Lead zirconate, PhZrO;

Lead zirconate titanate, Pb(Z1,Ti)O;

Lead lanthanum zirconate titanate, (Pb,La}{(Zr,TijO3

Polar nanoregions

Lead magnesium niobate, Po(Mg,gNbia)Os

Lead zirconate titanate, Pb(Zx,Ti)O3

Relaxor ferroelectric

Thermogravimetric analysis X-Ray diffraction

increasing La-doping concentration In particular, the films with 5 mol.% La-

doping simultaneously exhibit a quite high recoverable energy-storage density

(~7.0 vem") and a large enerpy-storage efficiency (~ 60.7%) under an gp of

1650 kV/em Moreover, dieleewie coustant of La-doped BZT thin films was found to be significantly improved, reaching the wiaximum value of 164 for 3 mol.% La-doped BZT thin film

These results indicated thal lead-free BalZr92sTigz3)O3 and Ta-doped Ba(21/asTia;;)O; thín films were expected to become a candidate materials for

cnergy-storage capacitors

Master student

(Sign and write fall name)

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

Figure 3.1L Hlectric field dependence of 2,4, and P,, values for La-doped BZ‘

thin films at various La doping contents measured until their corresponding

electric breakdown strength (2p) The data were calculated from the

corresponding #-# LOOPS ccsssscsessssssiesssssseisssssseeseessseeeseesssineeiess + 42

Figure 3.12 Dependence of volumetric energy-storage density (ae os recoverable energy-slorage đensity (17.„„), and cnergy-storage efficiency (17) on

applied electric field (or BZ.T thin fibns with various Ta doping conLents (a) 0%,

(b) 3%, (c) 5%, (d) 8% The data were calculated from the corresponding P-E

Figure 3.13 (a) Energy: storage © densities, recoverable energy-storage and (b)

energy-storage e[liciency were measured at the comresponding gp values, for

BZT thin films with various La doping contents 44

Figure 3.14 (a) Dielectric constant electric field (c-K) curves and (b) dielectric

loss curves of BZT thin films with various doping content, measurement at room

Figure 3.15 The operating-temperature dependence of (a) P-E keop, (©) Pinas Pr

and Py ?,-values for BZ'T thin film at an annealing temperature of 500 °C

The measurements were performed al 4000 kV/em and 1000 Ay 45

Figure 3.16 The operating-lomperalure dependence of (a) cnorgy storage densily (O) and (b) energy storage efficiency (y) for BZT thin film at annealing temperature of 500 °C The measurements were performed at 4000 kV/cm and

Figure 3.17 The Sequencies temperature dependence of of PE ! loops for BAT thin

film at annealing temperature of 500 °C The measurements were performed al

Figure 3.18 The operating-frequencies dependence of @) Pa P, and Prax - Py

values, (b) E, values, (c) energy storage density (U) and (d) energy-storage

efficiency (9) for BZT thin film BZT thin film al anmealing temperature of 500

°C The measurements were performed at 4000 kV/em and room temperature 47

Figure 3.19 a) Comparison of P-E hysteresis loops measured at different

charge-discharge oycles, (b) Pix and P, values as a function of number charge- discharge cveles under an applied electric field of 4000 kV/em and 1 kHz, for the

BAT thin film at annealing temperature of 500 °C The fatigue testing was

performed by applying a tpolar electric field of pulse height 200 KV/em and at

pulse width 100 KLIz (07 5 U8) ccccsssscessseeseesunssseeee sees .49

Figure 3.20 Dependence of (a) energy storage density and q@) energy storage efficiency () on cycling for BZT thin film at an annealing temperature of 500°C

The dala were calculated from the corresponding P-E hysleresis loops performed

at 1000 kVvem, 1 kHz and room temperature - - 49

increasing La-doping concentration In particular, the films with 5 mol.% La-

doping simultaneously exhibit a quite high recoverable energy-storage density

(~7.0 vem") and a large enerpy-storage efficiency (~ 60.7%) under an gp of

1650 kV/em Moreover, dieleewie coustant of La-doped BZT thin films was found to be significantly improved, reaching the wiaximum value of 164 for 3 mol.% La-doped BZT thin film

These results indicated thal lead-free BalZr92sTigz3)O3 and Ta-doped Ba(21/asTia;;)O; thín films were expected to become a candidate materials for

cnergy-storage capacitors

Master student

(Sign and write fall name)

Figure 3.1L Hlectric field dependence of 2,4, and P,, values for La-doped BZ‘

thin films at various La doping contents measured until their corresponding

electric breakdown strength (2p) The data were calculated from the

corresponding #-# LOOPS ccsssscsessssssiesssssseisssssseeseessseeeseesssineeiess + 42

Figure 3.12 Dependence of volumetric energy-storage density (ae os recoverable energy-slorage đensity (17.„„), and cnergy-storage efficiency (17) on

applied electric field (or BZ.T thin fibns with various Ta doping conLents (a) 0%,

(b) 3%, (c) 5%, (d) 8% The data were calculated from the corresponding P-E

Figure 3.13 (a) Energy: storage © densities, recoverable energy-storage and (b)

energy-storage e[liciency were measured at the comresponding gp values, for

BZT thin films with various La doping contents 44

Figure 3.14 (a) Dielectric constant electric field (c-K) curves and (b) dielectric

loss curves of BZT thin films with various doping content, measurement at room

Figure 3.15 The operating-temperature dependence of (a) P-E keop, (©) Pinas Pr

and Py ?,-values for BZ'T thin film at an annealing temperature of 500 °C

The measurements were performed al 4000 kV/em and 1000 Ay 45

Figure 3.16 The operating-lomperalure dependence of (a) cnorgy storage densily (O) and (b) energy storage efficiency (y) for BZT thin film at annealing temperature of 500 °C The measurements were performed at 4000 kV/cm and

Figure 3.17 The Sequencies temperature dependence of of PE ! loops for BAT thin

film at annealing temperature of 500 °C The measurements were performed al

Figure 3.18 The operating-frequencies dependence of @) Pa P, and Prax - Py

values, (b) E, values, (c) energy storage density (U) and (d) energy-storage

efficiency (9) for BZT thin film BZT thin film al anmealing temperature of 500

°C The measurements were performed at 4000 kV/em and room temperature 47

Figure 3.19 a) Comparison of P-E hysteresis loops measured at different

charge-discharge oycles, (b) Pix and P, values as a function of number charge- discharge cveles under an applied electric field of 4000 kV/em and 1 kHz, for the

BAT thin film at annealing temperature of 500 °C The fatigue testing was

performed by applying a tpolar electric field of pulse height 200 KV/em and at

pulse width 100 KLIz (07 5 U8) ccccsssscessseeseesunssseeee sees .49

Figure 3.20 Dependence of (a) energy storage density and q@) energy storage efficiency () on cycling for BZT thin film at an annealing temperature of 500°C

The dala were calculated from the corresponding P-E hysleresis loops performed

at 1000 kVvem, 1 kHz and room temperature - - 49

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Figure 2.6 Schematic of spin-coating and heat treatment process for producing

BZT thin films 26 Figure 2.7 Spin-coaling machine al, Inlemalional Traming Tnstilule for Matcrials Seienee (TLIME khung tuireiii 2 Figure 2.8 Schematic representation of the Drage’ s law for diffraction BỊ 28 Figure 2.9 The working principle diagram of X-ray diffractometer and the PANalytical X’Pert PRO system [48] khien "— ˆ Figure 2.10 The schematic drawing of a Sawyer-Tower circuit used for hysteresis measurement al ferrocleciric thin fil [49] 30

Figure 2.11, Equipment for measuring ferroelectric properties of materials BLZT (aix ACCT- TF2000) - - - 31 Figure 3.1 Cross-seclional SEM images of BZT bà films, grown om Py/Ti/SiO,/Si, at various annealing temperatures (a) 150 "C, (b) 500°C, (c) 600

°C, (d) 650%, (e) 675 °C, Œ) 700%C "_ Figure 3.2 (a) XRD pattems of BZT thin films, grown on ‘PYLVSiOyS, at various annealing temperatures, 7, (b) Schematic of the dependence of phase transition on annealing (emperalure, T, for BZT thin films 33

Figure 3.3 Polarization-electric field (P-2) hysteresis loops and th values of

Pree, Py and Pyyey P, for BET thin films at various annealing temperatures The

measurements were performed at 1000 kV/cm and 1 kllz 34

Figure 5.4 Electric field dependence of P,,., and, values for BZT thin films at

various annealing temperatwes, measured until their conesponding electric

breakdown strength (Egy) The dala were calculated from the corresporiding P-F

Tigure 3.5 ‘Dependence of vohmett ¢ enerpy- storage density Cv, recoverable

energy-storage density U,, and energy-storage efficiency (1) on applied electric

field for BZT thin films al various ammealing temperatures The dala were

calculated from the corresponding P-E loops 37

Figure 3.6, (4) Fnergy-storage densilies, recoverable energy-slorage and (b) energy-storage efficiency were measured at the corresponding Lp, values, for BZT thin films at various annealing temperatures 38 Figure 3.7 (a) Dielectric constant — electric field (e- 0 curves and by dielectric loss curves of BZY thin films at various annealing temperatures, measurement at

Figure 3.10 Polarivation-electric field 104 FR) liysteresis loops and (b) values of Prey, Py and Pag, - P, for BET thin films with various La doping contents (0-8 mol.%), The measurements were performed at 1000 kV/om and 1 kHz 41

increasing La-doping concentration In particular, the films with 5 mol.% La-

doping simultaneously exhibit a quite high recoverable energy-storage density

(~7.0 vem") and a large enerpy-storage efficiency (~ 60.7%) under an gp of

1650 kV/em Moreover, dieleewie coustant of La-doped BZT thin films was found to be significantly improved, reaching the wiaximum value of 164 for 3 mol.% La-doped BZT thin film

These results indicated thal lead-free BalZr92sTigz3)O3 and Ta-doped Ba(21/asTia;;)O; thín films were expected to become a candidate materials for

cnergy-storage capacitors

Master student

(Sign and write fall name)

Chemical Vapor Deposition

Differential scanning calorimetry

Barium titanate, BaTiO, Barium zirconate titanate, Ba(4r,Ti}O;

Barium lanthanum zirconate titanate, (Ba,La)(Zr.Ti)O;

Pulsed laser deposition

Lead zirconate, PhZrO;

Lead zirconate titanate, Pb(Z1,Ti)O;

Lead lanthanum zirconate titanate, (Pb,La}{(Zr,TijO3

Polar nanoregions

Lead magnesium niobate, Po(Mg,gNbia)Os

Lead zirconate titanate, Pb(Zx,Ti)O3

Relaxor ferroelectric

Thermogravimetric analysis X-Ray diffraction

Figure 2.6 Schematic of spin-coating and heat treatment process for producing

BZT thin films 26 Figure 2.7 Spin-coaling machine al, Inlemalional Traming Tnstilule for Matcrials Seienee (TLIME khung tuireiii 2 Figure 2.8 Schematic representation of the Drage’ s law for diffraction BỊ 28 Figure 2.9 The working principle diagram of X-ray diffractometer and the PANalytical X’Pert PRO system [48] khien "— ˆ Figure 2.10 The schematic drawing of a Sawyer-Tower circuit used for hysteresis measurement al ferrocleciric thin fil [49] 30

Figure 2.11, Equipment for measuring ferroelectric properties of materials BLZT (aix ACCT- TF2000) - - - 31 Figure 3.1 Cross-seclional SEM images of BZT bà films, grown om Py/Ti/SiO,/Si, at various annealing temperatures (a) 150 "C, (b) 500°C, (c) 600

°C, (d) 650%, (e) 675 °C, Œ) 700%C "_ Figure 3.2 (a) XRD pattems of BZT thin films, grown on ‘PYLVSiOyS, at various annealing temperatures, 7, (b) Schematic of the dependence of phase transition on annealing (emperalure, T, for BZT thin films 33

Figure 3.3 Polarization-electric field (P-2) hysteresis loops and th values of

Pree, Py and Pyyey P, for BET thin films at various annealing temperatures The

measurements were performed at 1000 kV/cm and 1 kllz 34

Figure 5.4 Electric field dependence of P,,., and, values for BZT thin films at

various annealing temperatwes, measured until their conesponding electric

breakdown strength (Egy) The dala were calculated from the corresporiding P-F

Tigure 3.5 ‘Dependence of vohmett ¢ enerpy- storage density Cv, recoverable

energy-storage density U,, and energy-storage efficiency (1) on applied electric

field for BZT thin films al various ammealing temperatures The dala were

calculated from the corresponding P-E loops 37

Figure 3.6, (4) Fnergy-storage densilies, recoverable energy-slorage and (b) energy-storage efficiency were measured at the corresponding Lp, values, for BZT thin films at various annealing temperatures 38 Figure 3.7 (a) Dielectric constant — electric field (e- 0 curves and by dielectric loss curves of BZY thin films at various annealing temperatures, measurement at

Figure 3.10 Polarivation-electric field 104 FR) liysteresis loops and (b) values of Prey, Py and Pag, - P, for BET thin films with various La doping contents (0-8 mol.%), The measurements were performed at 1000 kV/om and 1 kHz 41

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Figure 2.6 Schematic of spin-coating and heat treatment process for producing

BZT thin films 26 Figure 2.7 Spin-coaling machine al, Inlemalional Traming Tnstilule for Matcrials Seienee (TLIME khung tuireiii 2 Figure 2.8 Schematic representation of the Drage’ s law for diffraction BỊ 28 Figure 2.9 The working principle diagram of X-ray diffractometer and the PANalytical X’Pert PRO system [48] khien "— ˆ Figure 2.10 The schematic drawing of a Sawyer-Tower circuit used for hysteresis measurement al ferrocleciric thin fil [49] 30

Figure 2.11, Equipment for measuring ferroelectric properties of materials BLZT (aix ACCT- TF2000) - - - 31 Figure 3.1 Cross-seclional SEM images of BZT bà films, grown om Py/Ti/SiO,/Si, at various annealing temperatures (a) 150 "C, (b) 500°C, (c) 600

°C, (d) 650%, (e) 675 °C, Œ) 700%C "_ Figure 3.2 (a) XRD pattems of BZT thin films, grown on ‘PYLVSiOyS, at various annealing temperatures, 7, (b) Schematic of the dependence of phase transition on annealing (emperalure, T, for BZT thin films 33

Figure 3.3 Polarization-electric field (P-2) hysteresis loops and th values of

Pree, Py and Pyyey P, for BET thin films at various annealing temperatures The

measurements were performed at 1000 kV/cm and 1 kllz 34

Figure 5.4 Electric field dependence of P,,., and, values for BZT thin films at

various annealing temperatwes, measured until their conesponding electric

breakdown strength (Egy) The dala were calculated from the corresporiding P-F

Tigure 3.5 ‘Dependence of vohmett ¢ enerpy- storage density Cv, recoverable

energy-storage density U,, and energy-storage efficiency (1) on applied electric

field for BZT thin films al various ammealing temperatures The dala were

calculated from the corresponding P-E loops 37

Figure 3.6, (4) Fnergy-storage densilies, recoverable energy-slorage and (b) energy-storage efficiency were measured at the corresponding Lp, values, for BZT thin films at various annealing temperatures 38 Figure 3.7 (a) Dielectric constant — electric field (e- 0 curves and by dielectric loss curves of BZY thin films at various annealing temperatures, measurement at

Figure 3.10 Polarivation-electric field 104 FR) liysteresis loops and (b) values of Prey, Py and Pag, - P, for BET thin films with various La doping contents (0-8 mol.%), The measurements were performed at 1000 kV/om and 1 kHz 41

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Figure 1.5 Orientation of dipoles in the ferroelectric materials (a) absence of electric field (b} under electric field and (c) after removal of electric field [23] 6 Iigure 1.6 Temperature evolution of dielectric constant showing the characteristic temperatures in RFE Representative hysteresis loops for each

Figure 1.7 Hysteresis behavior in (a) ferroelectric and (b) relaxor materials [27]

Figure 1.12 (Color online) The typical dependence of (a) polarization and (b)

permittivity on electric field of ferroelectrics in the first quarter [30], L3 Vigure 1.13 Diagram of hysteresis and energy storage density for (a) linear

dielectrics, (b) lerroclectries, (c) relaxer [erroclevtrics, and (d) anli-[erreeicetrics

The green area in the first quadrant is the recoverable energy densily Uyeco, and

the red area is the energy loss U,,, [32] - - 14

Figure 1.14 Schematic of the perovskite structure of BaTiO; ‘@ Cubic lattice

(above Curie temperature, 120°C), (b) ‘Tetragonal lattice (below Curie

Figure 2.3 Example of processing routes to obtain sol-gel spin coatings [16] 23 Figure 2.4, Flow diagram for producing BZT and BLZT sols 24

1.13 Relaxor ferroelectric coi sean sine Ổ

1.2 Principles for High Energy-Storage in Dielectric Capacitors cece 10

1.2.1 Basic knowledge on dielectric capacitor

Measuring methods of cncrgy-storage deusity for dielectric

11

1.23 Potential dielectrics for high energy-storage application 14

1.3 Overview of barium titanate-based materials - - 15

1.3.2 Liffeels of doping on BaliO; properlie "¬¬

21 Fabrication of BZI and BLZT thin films by sol-gel spin coating

21.1 Overview of sol-gel spin coating method 20

21.2 Fabrication of BZT and BLZT Sols 23

2143 Fabrication of BZT and BLZT thin films 25

2.2 Methods to investigate the structure and properties of BZT and BLZT

3.1.2 — Ferroelectric properties and breakdown strength (Epp) 34

3.1.4 Dieleetrieproperiies Xueesssusoou 38

3.2 Hfeots of La-doping on properties of BZ/1 thn ñlme 38

3.2.4 Ferroelectrle prenerlies and breakdown strenpth (Eap) 41

3/23 — Energy-slorsge proporiies - - 42 3.24 Dielectric properties - - - 44 3.3 Thermal stability, frequency stability and fatigue endurance 45

Figure 2.6 Schematic of spin-coating and heat treatment process for producing

BZT thin films 26 Figure 2.7 Spin-coaling machine al, Inlemalional Traming Tnstilule for Matcrials Seienee (TLIME khung tuireiii 2 Figure 2.8 Schematic representation of the Drage’ s law for diffraction BỊ 28 Figure 2.9 The working principle diagram of X-ray diffractometer and the PANalytical X’Pert PRO system [48] khien "— ˆ Figure 2.10 The schematic drawing of a Sawyer-Tower circuit used for hysteresis measurement al ferrocleciric thin fil [49] 30

Figure 2.11, Equipment for measuring ferroelectric properties of materials BLZT (aix ACCT- TF2000) - - - 31 Figure 3.1 Cross-seclional SEM images of BZT bà films, grown om Py/Ti/SiO,/Si, at various annealing temperatures (a) 150 "C, (b) 500°C, (c) 600

°C, (d) 650%, (e) 675 °C, Œ) 700%C "_ Figure 3.2 (a) XRD pattems of BZT thin films, grown on ‘PYLVSiOyS, at various annealing temperatures, 7, (b) Schematic of the dependence of phase transition on annealing (emperalure, T, for BZT thin films 33

Figure 3.3 Polarization-electric field (P-2) hysteresis loops and th values of

Pree, Py and Pyyey P, for BET thin films at various annealing temperatures The

measurements were performed at 1000 kV/cm and 1 kllz 34

Figure 5.4 Electric field dependence of P,,., and, values for BZT thin films at

various annealing temperatwes, measured until their conesponding electric

breakdown strength (Egy) The dala were calculated from the corresporiding P-F

Tigure 3.5 ‘Dependence of vohmett ¢ enerpy- storage density Cv, recoverable

energy-storage density U,, and energy-storage efficiency (1) on applied electric

field for BZT thin films al various ammealing temperatures The dala were

calculated from the corresponding P-E loops 37

Figure 3.6, (4) Fnergy-storage densilies, recoverable energy-slorage and (b) energy-storage efficiency were measured at the corresponding Lp, values, for BZT thin films at various annealing temperatures 38 Figure 3.7 (a) Dielectric constant — electric field (e- 0 curves and by dielectric loss curves of BZY thin films at various annealing temperatures, measurement at

Figure 3.10 Polarivation-electric field 104 FR) liysteresis loops and (b) values of Prey, Py and Pag, - P, for BET thin films with various La doping contents (0-8 mol.%), The measurements were performed at 1000 kV/om and 1 kHz 41

Figure 2.6 Schematic of spin-coating and heat treatment process for producing

BZT thin films 26 Figure 2.7 Spin-coaling machine al, Inlemalional Traming Tnstilule for Matcrials Seienee (TLIME khung tuireiii 2 Figure 2.8 Schematic representation of the Drage’ s law for diffraction BỊ 28 Figure 2.9 The working principle diagram of X-ray diffractometer and the PANalytical X’Pert PRO system [48] khien "— ˆ Figure 2.10 The schematic drawing of a Sawyer-Tower circuit used for hysteresis measurement al ferrocleciric thin fil [49] 30

Figure 2.11, Equipment for measuring ferroelectric properties of materials BLZT (aix ACCT- TF2000) - - - 31 Figure 3.1 Cross-seclional SEM images of BZT bà films, grown om Py/Ti/SiO,/Si, at various annealing temperatures (a) 150 "C, (b) 500°C, (c) 600

°C, (d) 650%, (e) 675 °C, Œ) 700%C "_ Figure 3.2 (a) XRD pattems of BZT thin films, grown on ‘PYLVSiOyS, at various annealing temperatures, 7, (b) Schematic of the dependence of phase transition on annealing (emperalure, T, for BZT thin films 33

Figure 3.3 Polarization-electric field (P-2) hysteresis loops and th values of

Pree, Py and Pyyey P, for BET thin films at various annealing temperatures The

measurements were performed at 1000 kV/cm and 1 kllz 34

Figure 5.4 Electric field dependence of P,,., and, values for BZT thin films at

various annealing temperatwes, measured until their conesponding electric

breakdown strength (Egy) The dala were calculated from the corresporiding P-F

Tigure 3.5 ‘Dependence of vohmett ¢ enerpy- storage density Cv, recoverable

energy-storage density U,, and energy-storage efficiency (1) on applied electric

field for BZT thin films al various ammealing temperatures The dala were

calculated from the corresponding P-E loops 37

Figure 3.6, (4) Fnergy-storage densilies, recoverable energy-slorage and (b) energy-storage efficiency were measured at the corresponding Lp, values, for BZT thin films at various annealing temperatures 38 Figure 3.7 (a) Dielectric constant — electric field (e- 0 curves and by dielectric loss curves of BZY thin films at various annealing temperatures, measurement at

Figure 3.10 Polarivation-electric field 104 FR) liysteresis loops and (b) values of Prey, Py and Pag, - P, for BET thin films with various La doping contents (0-8 mol.%), The measurements were performed at 1000 kV/om and 1 kHz 41