Preparation and Study of Electrical Characteristics of (n-CdS/p-Ge) Thin-Film Heterojunction


A thin film (400±5 nm) of Germanium was deposited on the slide glass, thenanother thin film (200±3 nm) of Cadmium Sulphide directly deposited on the Ge thinfilm, with high purity (99.999%) Aluminum metal was used as O’hmic contact on twosides of heterojunction (n-CdS/p-Ge) by vacuum thermal evaporation technique.From ideality factor (n) values, the current transporting mechanism in theheterojunction was explained, where three regions in I-V curve were appeared, that is tosay, three mechanism of current transportation through the manufactured heterojunctionin this research were eventually existed, the saturation current (IS) was found for eachregion at different temperature (100, 200, 300) K.Through C-V measurements we found built – in potential (Vbi), the donordensity (ND), the difference between Fermi level and conduction band (Ön), thedifference between Fermi level and valance band (Öp), the conduction and valence bandsdiscontinuity (DEC, DEV), and the depletion regions width (Xn, Xp) of heterojunction (n-CdS/p-Ge) of the frequencies (1, 0.5) MHz.