Preparation and study of electrical characteristics of (n-cdsp-ge)‎ thin-film heterojunction

Abstract EN

A thin film (400 5 nm) of Germanium was deposited on the slide glass, then another thin film (200 3 nm) of Cadmium Sulphide directly deposited on the Ge thin film, with high purity (99.999 %) Aluminum metal was used as O’hmic contact on two sides of heterojunction (n-CdS / p-Ge) by vacuum thermal evaporation technique.

From ideality factor (n) values, the current transporting mechanism in the heterojunction was explained, where three regions in I-V curve were appeared, that is to say, three mechanism of current transportation through the manufactured heterojunction in this research were eventually existed, the saturation current (IS) was found for each region at different temperature (100, 200, 300) K.

Through C-V measurements we found built-in potential (Vbi), the donor density (ND), the difference between Fermi level and conduction band (Φn ), the difference between Fermi level and valance band (Φp), the conduction and valence bands discontinuity ( EC,  EV), and the depletion regions width (Xn, Xp) of heterojunction (n- CdS / p-Ge) of the frequencies (1, 0.5) MHz.