INVESTIGATION OF BUFFER LAYERS, FRONT AND BACK CONTACTS FOR ZnxCd1-xS/CdTe PHOTOVOLTAIC

A numerical analysis was executed utilizing Analysis ofMicroelectronic and Photonic Structures (AMPS 1D)simulator to explore the possibility of higher efficiencyand stable ZnxCd1-xS/CdTe cells among several cellstructures with indium tin oxide (ITO) and cadmiumstannate (Cd2SnO4) as front contact, zinc stannate(Zn2SnO4) and zinc oxide (ZnO) insertion as bufferlayer and antimony telluride (Sb2Te3) insertion withNickle (Ni) as back contact was conducted in theconventional (SnO2/CdS/CdTe/Ag) CdTe cell structuresin which CdS is replaced by zinc cadmium sulphide(ZnxCd1-xS) as window layer. Efficiency as high as18.0% has been found with 80 nm of ZnxCd1-xS windowlayer for x=0.05, 1 µm of CdTe layer and 100 nmZn2SnO4 buffer layer without Sb2Te3 back contact.However, ZnO insertion shows low conversionefficiency of 7.84% and 12.26%, respectively with andwithout Sb2Te3 back contact. Moreover, it was foundthat the cell normalized efficiency linearly decreaseswith the increasing operating temperature at thetemperature gradient of -0.25%/°C.