Semiconductor thin films and their junctions such as metal-semiconductor junctions and heterojunctions have received much attention due to their applications in various electronic and optoelectronic devices. The present studies were carried out for optical and electronic properties of vacuum deposited thin films of CdTe, ITO, CdS and ZnO and their Schottky barrier junctions such as Al/(p)CdTe, Ni/(n)CdS and Sn/(n)ZnO and heterojunctions such as (n)ITO/(p)CdTe, (n)CdS/(p) CdTe and (n)ZnO/(p)CdTe. The individual films were studied for transmittance, reflectance, absorbance, refractive index, extinction coefficient, energy gap, etc. Electrical properties studied were resistivity, conductivity, energy gap, photoconductivity, carrier life time, etc. The junction parameters such as barrier height, ideality factor, Richardson’s constant, etc. were calculated from the I-V characteristics of the junctions at different temperatures. From the I-V curves of the junctions under illumination the parameters like short-circuit current, open- circuit voltage, fill-factor, PV conversion efficiency, etc. were determined.