FIRST-PRINCIPLE CALCULATIONS OF BAND-STRUCTURES AND OPTICAL PROPERTIES OF SnS, Cu_2SnS_3 AND Cu_2ZnSnS_4 FOR PHOTOVOLTAICS

摘要

In order to find CIGS-replacing materials to be used for production of cheaper and environmentfriendly solar cells, we present computer simulation of structural, electronic and optical properties of SnS, Cu_2SnS_3and Cu_2ZnSnS_4 compounds performed in the frame of Density Functional Theory (DFT). According to ourcalculations, in spite of numerical underestimations of the band gap values, α-SnS, monoclinic Cu_2SnS_3 andCu_2ZnSnS_4 were found to have the averaged absorption coefficients the same order of magnitude in the visiblespectrum range as that of GaAs. Thus, these materials or their multilayer combinations can become adequate forCIGS substitution being built on neither nontoxic nor rare elements.