Combined theoretical studies of the optical characteristics of II-IV-V2 semiconductor thin films

• Numerical analysis for optical spectra of some chalcopyrite thin films is presented.
• Absorbance spectra are recorded at normal incidence of light.
• MgGeAs2 shows a considerably high optical absorption.
• A thickness of 3.2 μm is sufficient to absorb 90% of the incident light.

The optical absorbance of four ternary thin films, i.e. MgSiP2, MgGeP2, MgSiAs2, MgGeAs2 have been theoretically examined over a wide range of wavelength from 300 nm to 800 nm. The combination of first-principle electronic structure calculations and the optical matrix approach for modeling the multilayer assembly have been employed for theoretical studies. The analysis of the calculated absorbance spectra at room temperature with unpolarized light and normal incidence, revealed that MgGeAs2 with a direct energy band gap of 1.6 eV exhibit a considerable high optical absorption, where a thickness of 3.2 μm of this thin film is sufficient to absorb 90% of the incident light and generates a maximum photocurrent of ∼23 mA/cm2.

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