Effect of the Cadmium Telluride Deposition Method on the Covering Degree of Electrodes Based on Copper Nanowire Arrays
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In this work, we report the preparation of nanostructured electrodes based on dense arrays of vertically-aligned copper (Cu) nanowires (NWs) to be subsequently covered by cadmium telluride (CdTe) thin films, with great potential to be used within "substrate"-type photovoltaic cells based on A(II)-BVI heterojunctions. In particular, the multi-step preparation protocol presented here involves an electrochemical synthesis procedure within a supported anodic aluminum oxide (AAO) nanoporous template for first generating a homogeneous array of vertically-aligned Cu NWs, which are then further embedded within a compact CdTe thin film. In a second stage, we tested three deposition methods (vacuum thermal evaporation, VTE; radio-frequency magnetron sputtering, RF-MS; and electrochemical deposition, ECD) for use in obtaining CdTe layers potentially able to consistently penetrate the previously prepared Cu NWs array. A comparative analysis was performed to critically evaluate the morphological, optical, and structural properties of the deposited CdTe films. The presented results demonstrate that under optimized processing conditions, the ECD approach could potentially allow the cost-effective fabrication of absorber layer/collecting electrode CdTe/Cu nanostructured interfaces that could improve charge collection mechanisms, which in turn could allow the fabrication of more efficient solar cells based on A(II)-BVI semiconducting compounds.