Electrical and switching behavior of quaternary defect chalcopyrite CdInGaSe₄ thin films

Abstract

CdInGaSe₄ thin films were prepared by thermal evaporation technique. The amorphous nature of the thin films was confirmed by X-ray analysis. The elemental composition of thin film samples was determined by energy-dispersive X-ray spectrometry revealing the stoichiometric compositions of the material. The temperature and thickness dependences of DC electrical conductivity σ _DC were studied, in the temperature and thickness ranges (303–423 K) and (71–198 nm), respectively. The results indicate that the conduction occurs through a thermally activated process having two conduction levels. The switching phenomenon was studied; the obtained I–V curves are typical for memory switch. The value of V _th increases with film thicknesses, while it decreases exponentially with increasing temperature. The value of threshold field E _th calculated and found to decrease with increasing temperature. The ratio between the threshold activation energy Δɛ _th and the electrical activation energy ΔE _σ2 was calculated and found to be ($\frac{{\Delta \varepsilon_{\text{th}} }}{{\Delta E_{\sigma 2} }}$ ≈ 0.93 eV), which can be explained according to thermal model. Values of ΔT _breakdown were also calculated and found to increase with temperature.