Optical, electronic and elastic properties of ScAlN alloys in WZ and ZB phases: Prospective material for optoelectronics and solar cell applications
| Autor: | K. Almi, Sara Saada, Said Lakel |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science business.industry Band gap 02 engineering and technology 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences symbols.namesake 0103 physical sciences symbols Density of states Optoelectronics General Materials Science Direct and indirect band gaps Density functional theory Electrical and Electronic Engineering 0210 nano-technology business Absorption (electromagnetic radiation) Refractive index Debye model Wurtzite crystal structure |
| Zdroj: | Superlattices and Microstructures. 109:915-926 |
| ISSN: | 0749-6036 |
| DOI: | 10.1016/j.spmi.2017.06.025 |
| Popis: | To comprehend merits and demerits of Sc 0.25 Al 0.75 N alloys in WZ and ZB phases for optoelectronics and solar cell technology, we performed a comparative study of the elastic, electronic and optical properties of these alloys using first-principles methodology with density functional theory. The elastic constants (C ij , B, G, E, ν and B/G), longitudinal and shear wave velocities (v s , v l ) and Debye temperature θ D of ZB and WZ-Sc 0.25 Al 0.75 N alloys have been calculated for the first time. The calculated results show that ZB and WZ-Sc 0.25 Al 0.75 N alloys have the direct band gap and the ZB-Sc 0.25 Al 0.75 N alloy exhibit comparatively narrower energy gap than WZ. The density of states of W-Al 0.75 Sc 0.25 N and ZB-Sc 0.25 Al 0.75 N were analyzed. The peaks of imaginary dielectric function and absorption curves are at higher energy point for ZB-Sc 0.25 Al 0.75 N. The highest absorption of ZB-Sc 0.25 Al 0.75 N is 3.65 × 10 5 /cm at 14.26 eV, which is larger than wurtzite of 3.32 × 10 5 /cm at 11.22 eV. The average reflectivity of WZ-Sc 0.25 Al 0.75 N is lower than that of ZB-Sc 0.25 Al 0.75 N. Moreover wide energy gap of WZ-Sc 0.25 Al 0.75 N results in smaller values of the static refractive indices compared to ZB-Sc 0.25 Al 0.75 N. The comparison of the electronic and optical characteristics of the ZB-Sc 0.25 Al 0.75 N with those of WZ-Sc 0.25 Al 0.75 N endorses that ZB-Sc 0.25 Al 0.75 N can be a material of choice for optoelectronics and solar cell applications besides the WZ-Sc 0.25 Al 0.75 N. |
| Databáze: | OpenAIRE |
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