With dwindling energy reserves, Photovoltaic(PV) module which is one of the most promising renewable sources of energy is slowly becoming indispensable for world’s electricity production paradigm. Due to the low electrical resistance and high optical transparency in the visible range of the electromagnetic spectrum, Transparent Conducting Oxide (TCO) thin film(TF)s have found application as window electrode for fabrication of solar cell. Besides TCOs have wide application in display devices and other optoelectronic devices. This book mainly focuses on the fabrication and study of the optoelectronic properties of TCO thin films with special reference to PV application. This book also includes the fabrication and study of a heterojunction II-VI semiconductor solar cell using TCO as front electrode. It also highlights different methods used for the study of optoelectrical and structural properties of TF (e.g. SEM, XRD, thickness measurement, optical band gap, mobility, determination of carrier type, carrier concentration, conductivity etc.). This book is designed to serve as a handbook for the beginners who want to work in the field of thin film technology.