High-frequency and below bandgap anisotropic dielectric constants in α-(AlxGa1−x)2O3 (≤x≤1)
Abstract
A Mueller matrix spectroscopic ellipsometry approach was used to investigate the anisotropic dielectric constants of corundum α-(AlxGa1−x)2O3 thin films in their below bandgap spectral regions. The sample set was epitaxially grown using plasma-assisted molecular beam epitaxy on m-plane sapphire. The spectroscopic ellipsometry measurements were performed at multiple azimuthal angles to resolve the uniaxial dielectric properties. A Cauchy dispersion model was applied, and high-frequency dielectric constants are determined for polarization perpendicular (ε∞,⊥) and parallel (ε∞,∥) to the thin film c-axis. The optical birefringence is negative throughout the composition range, and the overall index of refraction substantially decreases upon incorporation of Al. We find small bowing parameters of the high-frequency dielectric constants with b⊥=0.386 and b∥=0.307.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 30, 2021
- Source ID
- 10.1063/5.0064528
Entities
People
- Debdeep Jena
- Huili Grace Xing
- J. A. Woollam
- Mathias Schubert
- Matthew Hilfiker
- Megan Stokey
- Rafał Korlacki
- Riena Jinno
- Ufuk Kılıç
- Yong-Jin Cho
Organizations
- Air Force Office of Scientific Research
- Cornell University
- Knut and Alice Wallenberg Foundation
- Kyoto University
- Linköping University
- National Science Foundation
- University of Nebraska–Lincoln