Investigation of defects in N+-CDS/P-CdTe solar cells

Two sets of samples (CdTe solar cells) were investigated at -1V within a temperature range of 300K-393K. We discuss Shockley-Read-Hall recombination /generation (SRH R-G) as applied to CdTe and the assumptions used to yield trap energy levels in CdTe. Observed activation energies of the J-V characterization made with Cu-containing back contact in one sample shows one slope while in another sample shows two distinct slopes in Arrhenius plot of ln (J₀T^-2) vs. 1000/T. Using published identification of the physical trap with energy level, we conclude that one sample does not have hole traps while the other cell shows deep levels corresponding to substitutional impurities of Cu and positive interstitial Cu_i²⁺.