SnO2/CdS-CdTe heterojunction has been fabricated by thermal evaporation technique, 0.05 µm thicknesses of SnO2 nanostructure was evaporated as thin layer to be used as an antireflection and as transparent conducting oxide. The prepared cell has been annealed at 573K for 180 minutes. The general morphology of SnO2 films was imaged by using Atomic Force Microscope (AFM), the image shows that the average grain size of the prepared film is constructed from nanostructure of dimensions in order of 72 nm. There are two wide peaks were presents at the x-ray pattern which were refers to SnO2 and is in agreement with the literature of American Standard of Testing Materials (ASTM).
The capacitance- voltage a measurement has studied at 102 Hz frequency, the capacitance- voltage measurements indicated that these cells are abrupt. The capacitance at zero bias, built in voltage, zero bias depletion region width and the carrier concentration have been calculated. The carrier transport mechanism for SnO2/CdS-CdTe heterojunction in dark is tunneling – recombination. The value of ideality factor is 1.56 and the reverse saturation current is 9.6×10-10A. Band energy lineup for SnO2/ n-CdS-p-CdTe heterojunction has been investigated by using I-V and C-V measurements.