Formation energies of carbon related defects in Cu2ZnSnS4

Cu₂ZnSnS₄ (CZTS) is one of the most promising absorber materials for highly efficient and low cost solar cells. A cost-effective method for the production of high quality CZTS makes use of the growth of nanocrystals in an amine solution of the involved metals, which can lead to considerable carbon incorporation in the final sample. In this study, preferred configurations and formation energies of carbon related defects in CZTS are calculated, leading to the finding, that two carbon atoms on a sulfur vacancy are a dominant defect, with minor influence on carrier lifetime, since it shows no mid-gap trapping states.