Quantum Confinement Effects in A Glass/Ito/Cds/Cdte Superstrate Structure Designed for Solar Energy Conversion
Investigation by XPS of the composition along the CdS/CdTe bilayer which is the active part of a CdTe-based solar cell, substantiated by Kelvin Probe work functions measurements, revealed existence of quantum wells near boundaries of both parts of the bilayer that affect the performance of solar cell. Photoluminescence measurements confirm the existence of quantum wells and of the corresponding blue shift of electron transition energies. Analysis of energy band diagram of the structure shows that the bilayer is of n+-n character (i.e. without p-n junction) and has several potential barriers that are responsible for the photo voltage generated by illumination. Traditional treatment with CdCl2 enhances the barrier at n+-n interface and improves the cellís characteristics.
Keywords- Quantum Confinement, Solar Cell, CdS/CdTe Active Layer, Band Diagram.