Crystallographic study on CdS/CdTe heterostructure for 15% efficiency thin film solar cells

Crystallographic properties of CdS as well as their influence on the subsequent growth of CdTe and on the formation of the CdTe_1-xS_x interlayer have been investigated for fabricating high efficiency thin film solar cells, employing X-ray diffraction measurements. In hexagonal CdS films, the first preferentially oriented [002] grains are grown having a lattice match with the second preferentially oriented (103) grains. The degree of cubic (111) preferential orientation of CdTe increases with increasing the hexagonal CdS [002] grain size. Furthermore, when changes in the CdS [002] grain sizes are small, the degree of (111) preferential orientation of CdTe increases with increasing the hexagonal CdS (103) grain size, of which twice lattice spacing is considerably close to the lattice spacing of CdTe (111). So far, applying crystallographic study on the CdS/CdTe heterostructure, we have achieved the conversion efficiency of 15.3%.