Surface analysis of selective-area deposition of cadmium telluride via close-spaced sublimation

After a long journey thin film solar cells based on CdTe arrived at lab efficiencies of 16% and large area module efficiencies of over 10% but there is no reason why they should not be better because the theoretical band model predicts a 29% efficiency. Therefore a lot of effort will continue on the research of better efficiencies, it is thought that the problem is the non-uniformity encounter at the microscopic level on the CdTe layer, therefore a study of grain sizes for different solar cells will be performed, to see if there is any correlation between the grain size and the deposition parameters, because for the future work a grid to pattern the solar cell is going to be used to increase the uniformity, in hopes of improve the solar cell efficiency. There are indications that the smaller the grain size, the smaller the collected current [1]. Another problem is the composition of the p-type CdTe layer; thus, a study of the variation in composition as a function of depth of a Te-rich solar cell was performed using the AES technique to obtain the concentrations of Cd and Te. XPS was used to calibrate the data obtained with AES because the sensitivity factors for AES are not accurate and SIMS technique was used to sputter the surface down to the glass of the cell to get a depth profile