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The effects of post-deposition processes such as CdCl 2 dip and/or annealing in air on the material and device properties of vacuum-evaporated Au-CdTe/CdS-TO heterojunction solar cells have been investigated. The CdCl 2 dip followed by air annealing at 300 • C for 5 min improved the device efficiency significantly, resulting in decreased CdTe resistivity and enhanced grain size. The temperature-dependent current-voltage analysis indicated that above 280 K interface recombination dominates the current transport mechanism for the as-grown samples, while depletion region recombination starts to be dominant after annealing the samples with CdCl 2 . Below 280 K multistep tunnelling is identified to be the dominant transport mechanism. Frequency-dependent capacitance-voltage studies revealed that after annealing with CdCl 2 the density of interface states decreases and the quality of the heterointerface improves. The capacitance of the CdS/CdTe heterojunctions has been analysed using a model based on the existence of a single dominant trap level, identified at 0.40 eV above the valence band with a concentration of 5.1 × 10 15 cm −3 .

In this study, device behavior of amorphous InSe thin films was investigated through I-V, C-V and spectral response measurements onto SnO 2 /p-InSe/metal Schottky diode structures. Various metal contacts such as Ag, Au, Al, In and C were deposited onto amorphous p-InSe films by the thermal evaporation technique. The best rectifying contact was obtained in a SnO 2 /p-InSe/Ag Schottky structure from I-V measurements, while the Au contact had poor rectification. Other metal contacts (Al, In and C) showed almost ohmic non-rectifying behaviors for all samples. The ideality factor and barrier height values with the Ag contact were found to be 2 and 0.7 eV, respectively.

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