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DS: Fachverband Dünne Schichten
DS 8: Thin Film Properties III
DS 8.3: Talk
Tuesday, March 28, 2023, 12:00–12:15, SCH A 315
Heteroepitaxial Growth of Ultrawide Bandgap Cubic Spinel Zn2GeO4 Thin Films by Pulsed Laser Deposition — •Jingjing Yu, Sijun Luo, and Marius Grundmann — Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Universität Leipzig, 04103 Leipzig
It is significant to explore new ultrawide bandgap oxides thin films with a bandgap larger than 4 eV for potential applications in power electronics and deep-UV photodetectors. Cubic spinel Zn2GeO4 is a high-temperature and high-pressure phase which was originally synthesized at 1600 ∘C and 3 GPa. To date the experimental results on physical properties and thin film growth of cubic spinel Zn2GeO4 are not available. In this study, we report the heteroepitaxial growth of cubic spinel Zn2GeO4 thin films on cubic spinel MgAl2O4 single crystal substrates by using pulsed laser deposition at about 800 ∘C. Combining the analysis results from XRD 2theta-omega scans and rocking curves with the AFM surface morphologies, it is concluded that the oxygen partial pressure of around 0.05~0.10 mbar is optimal for growing high-quality Zn2GeO4 epitaxial thin films. Phi-scan results confirm the single-domain epitaxy of (100)-, (110)- and (111)-oriented Zn2GeO4 epitaxial thin films grown on (100), (110) and (111) MgAl2O4 substrates, respectively. The dielectric function of the cubic spinel Zn2GeO4 epitaxial thin films was measured by spectroscopic ellipsometry, indicating a bandgap energy greater than 4.5 eV. This work advances the fundamental research on ultrawide bandgap cubic spinel Zn2GeO4 epitaxial thin films.