Textured fabrication of Cadmium Sulphide Cadmium Telluride thin film Photovoltaic cell with back contacts

Abstract

Thin film photovoltaic (PV) using CdS/CdTe heterostructure is being studied extensively for reducing the cost of PV panels. Transparent conductive oxide (TCO) is used as one of the electrodes for allowing the photons to enter the window layer of the solar cell. But most of the TCO are responsible for obstructing about 20 % of the incoming radiation. So in this study the novel idea of incorporating both top and bottom electrodes on the substrate of the PV cell is presented. This study also explains the importance of fabricating different nanostructures of thin film for increasing the junction area and to increase the light absorption. In order to increase the junction area of thin film solar cell, microwall, nanopore, nanowall and nanopillar structures have been fabricated. The simulation results from ATLAS/SILVACO tool was also used to support the increase in photocurrent with the help of patterned surface. Even though the fabricated devices showed conversion efficiency of 0.08%, by optimization of the material parameters such as the grain growth, deposition technique and annealing temperature the electrical parameters can be improved. The scope of this work is to introduce the concept of back contacts and effect of texturing on thin film CdS/CdTe solar cell. newline