Autor: |
Xuan Au Nguyen, Thi Minh Hai Nguyen, Tae Jung Kim, Long Van Le, Tung Hoang Nguyen, Bogyu Kim, Kyujin Kim, Wonjun Lee, Sunglae Cho, Young Dong Kim |
Jazyk: |
angličtina |
Rok vydání: |
2021 |
Předmět: |
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Zdroj: |
Crystals, Vol 11, Iss 5, p 548 (2021) |
Druh dokumentu: |
article |
ISSN: |
2073-4352 |
DOI: |
10.3390/cryst11050548 |
Popis: |
We report the dielectric tensors on the cleavage plane of biaxial SnSxSe1-x alloys in the spectral energy region from 0.74 to 6.42 eV obtained by spectroscopic ellipsometry. Single-crystal SnSxSe1-x alloys were grown by the temperature-gradient method. Strongly anisotropic optical responses are observed along the different principal axes. An approximate solution yields the anisotropic dielectric functions along the zigzag (a-axis) and armchair (b-axis) directions. The critical point (CP) energies of SnSxSe1-x alloys are obtained by analyzing numerically calculated second derivatives, and their physical origins are identified by energy band structure. Blue shifts of the CPs are observed with increasing S composition. The fundamental bandgap for Se = 0.8 and 1 in the armchair axis arises from band-to-band transitions at the M0 minimum point instead of the M1 saddle point as in SnS. These optical data will be useful for designing optoelectronic devices based on SnSxSe1-x alloys. |
Databáze: |
Directory of Open Access Journals |
Externí odkaz: |
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