Defect signatures in copper gallium diselenide

Results of investigation on defect levels by photocurrent and capacitance spectroscopy methods in wide-gap photovoltaic semiconductor CuGaSe₂ (CGSe) are presented. Agreement of defect levels signatures obtained by using various spectroscopic methods and regardless on material morphology is shown. The influence of measurement conditions and material properties on defect levels parameters is reported. Presented are experimental evidences that some of the observed level by various methods of defect spectroscopy, gives defect parameters correlated according to the Meyer - Neldel Rule (MNR). The signatures of defect levels in the epitaxial and polycrystalline CGSe are presented and, whenever possible, the characteristic parameters describing MNR are given.