Azimuthal angle dependent dielectric function of SnS by ellipsometry

• Published in: Journal of the Korean Physical Society 2022, 80(1), , pp.59-62
• Main Authors: Nguyen, Xuan Au, Jung, Yong Woo, Kim, Young Dong, Van Le, Long, Nguyen, Hoang Tung, Kim, Tae Jung
• Format: Article
• Language: English
• Subjects: Critical point; Crystal structure; Dielectric strength; Mathematical and Computational Physics; Original Paper - Condensed Matter; Particle and Nuclear Physics; Physics; Physics and Astronomy; Spectroellipsometry; Theoretical; 물리학
• ISSN: 0374-4884; 1976-8524
• DOI: 10.1007/s40042-021-00364-z

Since α-SnS has optically strong anisotropic characteristics, a simple method to determine its crystal orientation is strongly needed in device engineering. In this report, by measuring dielectric function ε  =  ε 1  +  iε 2 of α-SnS in the 1–5 eV spectral region with the full azimuthal angle range, we could find a simple relationship between measured dielectric function values and the orientation of the α-SnS crystal axis. Therefore, during the device manufacturing process, one can use spectroscopic ellipsometry to quickly measure the dielectric response of the α-SnS region of the device to correctly orient the SnS along the preferred direction for the best performance of the device. We also performed the azimuthal angle-dependent analysis of the critical points (CP) analysis, which shows that the positions of CP energies are basically invariant, while their amplitudes and lineshapes strongly depend on the azimuthal angle.