Electronic and Optical Modeling of Solar Cell Compounds CuGaSe2 and CuInSe2

• Published in: Journal of electronic materials 2011-11, Vol.40 (11), p.2197-2208
• Main Authors: Soni, Amit, Dashora, Alpa, Gupta, Vikas, Arora, C. M., Rérat, M., Ahuja, B. L., Pandey, Ravindra
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Electronics; Electronics and Microelectronics; Energy; Exact sciences and technology; Instrumentation; Materials; Materials Science; Methods of electronic structure calculations; Natural energy; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Photovoltaic conversion; Physics; Solar cells. Photoelectrochemical cells; Solar energy; Solid State Physics
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-011-1739-1

We present dielectric-function-related optical properties such as absorption coefficient, refractive index, and reflectivity of the semiconducting chalcopyrites CuGaSe 2 and CuInSe 2 . The optical properties were calculated in the framework of density functional theory (DFT) using linear combination of atomic orbitals (LCAO) and full-potential linearized augmented plane wave (FP-LAPW) methods. The calculated spectral dependence of complex dielectric functions is interpreted in terms of interband transitions within energy bands of both chalcopyrites; for example, the lowest energy peak in the spectra for CuGaSe 2 corresponds to interband transitions from Ga/Se-4p → Ga-4s while that for CuInSe 2 emerges as due to transition between Se-4p → In-5s bands. The calculated dielectric constant, , for CuInSe 2 is higher than that of CuGaSe 2 . The electronic structure of both compounds is reasonably interpreted by the LCAO (DFT) method. The optical properties computed using the FP-LAPW model (with scissor correction) are close to the spectroscopic ellipsometry data available in the literature.