Deep level transient spectroscopy of CdS/CdTe thin film solar cells

Abstract

Deep levels in polycrystalline n-CdS/p-CdTe photovoltaic structures have been studied by deep level transient spectroscopy (DLTS). The results were obtained from cells which have undergone different post-deposition treatment (as-deposited, heat treated, and heat treated in the presence of CdCl2). The DLTS results showed a deep level distribution independent of the post-deposition treatment. For all samples the spectra were dominated by a hole trap, localized at EV+0.48 eV. Metastable hole and electron traps were also observed, mainly in the heat treated (with and without a CdCl2 layer) devices.