Strain and Layer Modulations of Optical Absorbance and Complex Photoconductivity of Two-Dimensional InSe: A Study Based on GW0+BSE Calculations
Since the definitions of the two-dimensional (2D) optical absorption coefficient and photoconductivity are independent of the thickness of 2D materials, they are more suitable than the dielectric function to describe the optical properties of 2D materials. Based on the many-body GW method and the Be...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Crystals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4352/15/7/666 |
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| Summary: | Since the definitions of the two-dimensional (2D) optical absorption coefficient and photoconductivity are independent of the thickness of 2D materials, they are more suitable than the dielectric function to describe the optical properties of 2D materials. Based on the many-body GW method and the Bethe–Salpeter equation, we calculated the quasiparticle electronic structure, optical absorbance, and complex photoconductivity of 2D InSe from a single layer (1L) to three layers (3L). The calculation results show that the energy difference between the direct and indirect band gaps in 1L, 2L, and 3L InSe is so small that strain can readily tune its electronic structure. The 2D optical absorbance results calculated taking into account exciton effects show that light absorption increases rapidly near the band gap. Strain modulation of 1L InSe shows that it transforms from an indirect bandgap semiconductor to a direct bandgap semiconductor in the biaxial compressive strain range of −1.66 to −3.60%. The biaxial compressive strain causes a slight blueshift in the energy positions of the first and second absorption peaks in monolayer InSe while inducing a measurable redshift in the energy positions of the third and fourth absorption peaks. |
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| ISSN: | 2073-4352 |