The Fabrication and Characterization of CdTe/PbTe Superlattice on ITO/Glass Substrates for the Absorber Layer of a Solar Cell

Fei Qin, Amal Kabalan, Pritpal Singh Villanova University, Villanova, PA, United States

CdTe/PbTe superlattice films are promising materials served as the absorber layer of the solar cells. The aim of this study was, using the Electrochemical Atomic Layer Deposition (EC-ALD) system, to fabricate CdTe/PbTe superlattice film on the low-cost and transparent Indium Tin Oxide (ITO). In our experiments, cyclic voltammetry was performed to study the Underpotential Deposition (UPD) of the constituent compounds. We used coulometry method to monitor the growth of monolayers (MLs) of the superlattice. These two techniques helped us obtain appropriate deposition potentials. A 40nm thick CdTe/PbTe superlattice film was eventually obtained. The chemical composition of the film determined by Energy-Dispersive X-ray Spectroscopy (EDS) was what we hypothesized. Our results provide compelling evidence that ITO is a suitable substrate for the fabrication of CdTe/PbTe superlattice by using EC-ALD system. The crystallinity and the bandgaps of the films will be examined in the near future.