Band gap shifting of CdTe/PbTe superlattices on ITO for solar cell

Electrochemical Atomic Layer Deposition (EC-ALD) has been used to fabricate three different superlattice structures of CdTe/PbTe thin films on ITO coated glass: (CdTe20/PbTe20)3, (CdTe10/PbTe20)3 and (CdTe5/PbTe20)3. These are intended to serve as the absorber layer of a solar cell. In our experiments, Cyclic Voltammetry (CV) and current monitoring helped us obtain appropriate deposition potentials. The grain sizes of the superlattices were studied by using Scanning Electron Microscopy (SEM). The chemical composition of the films was determined by Energy-Dispersive X-ray Spectroscopy (EDS). Optical absorption measurements were made in order to determine the band gap energy of the deposited films. We successfully shifted the bandgaps of CdTe/PbTe superlattices on ITO from 1.9 eV to 3.2 eV by changing the proportion of CdTe in the CdTe/PbTe pair.