The change of the spontaneous polarization due to a change of temperature is known as the pyroelectric effect and is restricted to crystalline, non-centrosymmetric and polar matter. Its main application is the utilization in infrared radiation sensors, but usage for waste heat energy harvesting or chemical catalysis is also possible. A precise quantification, i.e. the measurement of the pyroelectric coefficient p, is inevitable to assess the performance of a material. Hence, a comprehensive overview is provided in this work, which summarizes and evaluates the available techniques to characterize p. A setup allowing the fully automated measurement of p by utilizing the Sharp-Garn method and the measurement of ferroelectric hysteresis loops is described. It was used to characterize and discuss the behavior of p with respect to the temperature of the doped bulk III-V compound semiconductors gallium nitride and aluminum nitride and thin films of doped hafnium oxide, as reliable data for these materials is still missing in the literature. Here, the nitride-based semiconductors show a comparable small p and temperature dependency, which is only slightly affected by the incorporated dopant, compared to traditional ferroelectric oxides. In contrast, p of HfO2 thin films is about an order of magnitude larger and seems to be affected by the present dopant and its concentrations, as it is considered to be responsible for the formation of the polar orthorhombic phase.:1. Motivation and Introduction
2. Fundamentals
2.1. Dielectrics and their Classification
2.2. Polarization
2.3. Pyroelectricity
2.4. Ferroelectricty
2.5. Phase Transitions
2.6. Applications and Figures of Merit
3. Measurement Methods for the Pyroelectric Coefficient
3.1. General Considerations
3.1.1. Heating Concepts
3.1.2. Thermal Equilibrium
3.1.3. Electric Contact
3.1.4. Separation of Contributions
3.1.5. Thermally Stimulated Currents
3.2. Static Methods
3.2.1. Charge Compensation Method
3.2.2. Hysteresis Measurement Method
3.2.3. Direct Electrocaloric Measurement
3.2.4. Flatband Voltage Shift
3.2.5. X-ray Photoelectron Spectroscopy Method
3.2.6. X-ray Diffraction and Density Functional Theory
3.3. Dynamic Methods
3.3.1. Temperature Ramping Methods
3.3.2. Optical Methods
3.3.3. Periodic Pulse Technique
3.3.4. Laser Intensity Modulation Methods
3.3.5. Harmonic Waveform Techniques
4. Pyroelectric and Ferroelectric Characterization Setup
4.1. Pyroelectric Measurement Setup
4.1.1. Setup and Instrumentation
4.1.2. Automated Sharp-Garn Evaluation of Pyroelectric Coefficients
4.1.3. Further Examples
4.2. Hysteresis Loop Measurements
4.2.1. Instrumentation
4.2.2. Measurement and Evaluation
4.2.3. Examples
5. Investigated Material Systems
5.1. III-Nitride Bulk Semiconductors GaN and AlN
5.1.1. General Structure and Spontaneous Polarization
5.1.2. Applications
5.1.3. Crystal Growth and Doping
5.1.4. Pyroelectricity
5.2. Hafnium Oxide Thin Films
5.2.1. General Structure and Applications
5.2.2. Polar Properties in Thin Films
5.2.3. Doping Effects
5.2.4. Pyro- and Piezoelectricity
6. Results
6.1. The Pyroelectric Coefficient of Free-standing GaN and AlN
6.1.1. Sample Preparation
6.1.2. Pyroelectric Measurements
6.1.3. Lattice Influence
6.1.4. Slope Differences
6.2. Pyroelectricity of Doped Hafnium Oxide
6.2.1. Sharp-Garn Measurement on Thin Films
6.2.2. Effects of Silicon Doping
6.2.3. Dopant Comparison
7. Summary and Outlook
A. Pyroelectric Current and Phase under Periodic Thermal Excitation
B. Loss Current Correction for Shunt Method
C. Conductivity Correction
D. Comparison of Pyroelectric Figures of Merit
Bibliography
Publication List
Acknowledgments / Die Änderung der spontanen Polarisation durch eine Änderung der Temperatur ist bekannt als der pyroelektrische Effekt, welcher auf kristalline, nicht-zentrosymmetrische und polare Materie beschränkt ist. Er findet vor allem Anwendung in Infrarot-Strahlungsdetektoren, bietet aber weitere Anwendungsfelder wie die Niedertemperatur-Abwärmenutzung oder die chemische Katalyse. Eine präzise Quantifizierung, d. h. die Messung des pyroelektrischen Koeffizienten p, ist unabdingbar, um die Leistungsfähigkeit eines Materials zu bewerten. Daher bietet diese Arbeit u.a. einen umfassenden Überblick und eine Bewertung der verfügbaren Messmethoden zur Charakterisierung von p. Weiterhin wird ein Messaufbau beschrieben, welcher die voll automatisierte Messung von p mit Hilfe der Sharp-Garn Methode und auch die Charakterisierung der ferroelektrischen Hystereseschleife ermöglicht. Aufgrund fehlerender Literaturdaten wurde dieser Aufbau anschließend genutzt, um den temperaturabhängigen pyroelektrischen Koeffizienten der dotierten III-V-Verbindungshalbleiter Gallium- und Aluminiumnitrid sowie dünner Schichten bestehend aus dotiertem Hafniumoxid zu messen und zu diskutieren. Im Vergleich zu klassichen ferroelektrischen Oxiden zeigen dabei die nitridbasierten Halbleiter einen geringen pyroelektrischen Koeffizienten und eine kleine Temperaturabhängigkeit, welche auch nur leicht durch den vorhandenen Dotanden beeinflusst werden kann. Dagegen zeigen dünne Hafniumoxidschichten einen um eine Größenordnung größeren pyroelektrischen Koeffizienten, welcher durch den anwesenden Dotanden und seine Konzentration beeinflusst wird, da dieser verantwortlich für die Ausbildung der polaren, orthorhombischen Phase gemacht wird.:1. Motivation and Introduction
2. Fundamentals
2.1. Dielectrics and their Classification
2.2. Polarization
2.3. Pyroelectricity
2.4. Ferroelectricty
2.5. Phase Transitions
2.6. Applications and Figures of Merit
3. Measurement Methods for the Pyroelectric Coefficient
3.1. General Considerations
3.1.1. Heating Concepts
3.1.2. Thermal Equilibrium
3.1.3. Electric Contact
3.1.4. Separation of Contributions
3.1.5. Thermally Stimulated Currents
3.2. Static Methods
3.2.1. Charge Compensation Method
3.2.2. Hysteresis Measurement Method
3.2.3. Direct Electrocaloric Measurement
3.2.4. Flatband Voltage Shift
3.2.5. X-ray Photoelectron Spectroscopy Method
3.2.6. X-ray Diffraction and Density Functional Theory
3.3. Dynamic Methods
3.3.1. Temperature Ramping Methods
3.3.2. Optical Methods
3.3.3. Periodic Pulse Technique
3.3.4. Laser Intensity Modulation Methods
3.3.5. Harmonic Waveform Techniques
4. Pyroelectric and Ferroelectric Characterization Setup
4.1. Pyroelectric Measurement Setup
4.1.1. Setup and Instrumentation
4.1.2. Automated Sharp-Garn Evaluation of Pyroelectric Coefficients
4.1.3. Further Examples
4.2. Hysteresis Loop Measurements
4.2.1. Instrumentation
4.2.2. Measurement and Evaluation
4.2.3. Examples
5. Investigated Material Systems
5.1. III-Nitride Bulk Semiconductors GaN and AlN
5.1.1. General Structure and Spontaneous Polarization
5.1.2. Applications
5.1.3. Crystal Growth and Doping
5.1.4. Pyroelectricity
5.2. Hafnium Oxide Thin Films
5.2.1. General Structure and Applications
5.2.2. Polar Properties in Thin Films
5.2.3. Doping Effects
5.2.4. Pyro- and Piezoelectricity
6. Results
6.1. The Pyroelectric Coefficient of Free-standing GaN and AlN
6.1.1. Sample Preparation
6.1.2. Pyroelectric Measurements
6.1.3. Lattice Influence
6.1.4. Slope Differences
6.2. Pyroelectricity of Doped Hafnium Oxide
6.2.1. Sharp-Garn Measurement on Thin Films
6.2.2. Effects of Silicon Doping
6.2.3. Dopant Comparison
7. Summary and Outlook
A. Pyroelectric Current and Phase under Periodic Thermal Excitation
B. Loss Current Correction for Shunt Method
C. Conductivity Correction
D. Comparison of Pyroelectric Figures of Merit
Bibliography
Publication List
Acknowledgments
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:33969 |
| Date | 15 May 2019 |
| Creators | Jachalke, Sven |
| Contributors | Meyer, Dirk C., Mikolajick, Thomas, TU Bergakademie Freiberg |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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