Using the first principles calculations, we explored the optical properties of the two-dimensional α-GeTe structure. The 2D monolayer α-GeTe had an indirect band gap of 1.79 eV, and that indirect band gap was still observed in the bilayer although the band gap had decreased to 0.61 eV. We found that the optical band gap was much larger than the electrical band gap, which was due to the indirect band gap feature of the 2D α-GeTe system. In both systems, we found a very large refractive index in the visible range. Particularly, the bilayer system had a refractive index larger than 2.5 for blue light. Furthermore, the bilayer structure was found to have a larger reflectivity at ultraviolet frequencies. Consequently, we propose that the bilayer α-GeTe film can be utilized for potential optical device applications.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
K. S. Novoselov et al., Nature 438, 197 (2005).
M. Long et al., Sci. Adv. 3, e1700589 (2017).
M. U. Farooq, A. Hashmi and J. Hong, Surf. Sci. 634, 25 (2015).
L. Huang et al., Nano Lett. 17, 1161 (2017).
B. Marfoua and J. Hong, Physica E 111, 79 (2019).
M. Chhowalla, Z. Liu and H. Zhang, Chem. Soc. Rev. 44, 2584 (2015).
K. F. Mak, D. Xiao and J. Shan, Nat. Photon. 12, 451 (2018).
K. Kang et al., Nat. Mater. 18, 324 (2019).
A. K. Singh and R. G. Hennig, Appl. Phys. Lett. 105, 042103 (2014).
X. Zhang, Z. Yang and Y. Chen, J. Appl. Phys. 122, 064101 (2017).
A. Shafique and Y-H. Shin, Sci. Rep. 7, 506 (2017).
P. Zhang et al., Nanoscale 10, 15989 (2018).
T. Gwon et al., Chem. Mater. 28, 7158 (2016).
H. L. Kagdada, P. K. Jha, P. Śpiewak and K. J. Kurzydłowski, J. Appl. Phys. 124, 235701 (2018).
M. Qiao, Y. Chen, Y. Wang and Y. Li, J. Mater. Chem. A 6, 4119 (2018).
G. Kresse and D. Joubert, Phys. Rev. B 59, 1758 (1999).
P. Blochl, Phys. Rev. B 50, 17953 (1994).
G. Kresse and J. Furthmüller, Phys. Rev. B 54, 11169 (1996).
J. P. Perdew, K. Burke and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996).
S. Grimme, J. Comput. Chem. 27, 1787 (2006).
P. Blaha et al., WIEN2k: An Augmented Plane Wave+Local Orbitals Program for Calculating Crystal Properties (Vienna University of Technology, Vienna, 2001).
D. Zhang et al., Nanoscale Res. Lett. 13, 400 (2018).
T. Hu, A. Hashmi and J. Hong, Nanotechnology 26, 415702 (2015).
This work was supported by a research grant from Pukyong National University (2019).
About this article
Cite this article
Marfoua, B., Hong, J. Optical Properties of a Two-Dimensional GeTe Layer. J. Korean Phys. Soc. 76, 221–225 (2020). https://doi.org/10.3938/jkps.76.221
- Optical property
- 2D α-GeTe