Investigations of physical properties of lithium-based chalcopyrite semiconductors: non-toxic materials for photovoltaic applications

The ab-initio calculations have been executed for structural, electronic and optical properties of LiAlTe2, LiGaTe2 and LiInTe2 chalcopyrite structured solids and these calculations are grounded on the principle of density functional theory employed into the full potential augmented plane wave method. The computed lattice constants oscillating from a = 6.257 angstrom to 6.450 angstrom and c = 12.044 angstrom to 12.256 angstrom for LiXTe2 (X=Al, Ga and In) and also these values consistent with experimentally existed lattice constants. From the study of electronic band-gap, it confirms that these compounds are good semiconductors with direct band-gaps from 2.22 eV, 1.48 eV and 1.61 eV for LiXTe2 (X=Al, Ga and In). The result of optical properties confirms that these chalcopyrite semiconductors can be the fortunate compounds for the photovoltaic applications.