C-V and I-V Characterisation of CdS/CdTe Thin Film Solar Cell Using Defect Density Model

Abstract

This paper presents a detailed study of the current-voltage (I-V) and capacitance-voltage (C-V) measurements made on a CdS/CdTe based solar cell by numerical modeling. Implementation of the simulated cell having a superstrate configuration was done with the help of SCAPS program using defect density model. The I-V characterisation includes window and absorber layer optimisation based on various factors including the impurity doping concentration, thickness and defect density. The energy band diagram, spectral response and currentvoltage plot of the optimised cell configuration are shown. C-V characterisation (Mott-Schottky analysis) of the solar cell is conducted at different low frequencies to determine the flatband potential, carrier concentration and to validate the reliability of the results. The optimum device performance was obtained when the active layer was 2 gm thick with a doping level of 1/10|5/cm3.