Research on the photoresponse current and photosensitive properties of Cu2ZnSnS4 thin film prepared by sulfurization of a sputtered metal precursor

Abstract

The photoresponse current and photosensitive properties under different electrical field were studied for Cu2ZnSnS4 films. A persistent photoconductivity effect of Cu2ZnSnS4 film was observed and the effect of the electrical field on the decay time of photo excited current was investigated. The decay time of photo excited current of CZTS decreased from 378 s to 0.341 s with the electrical field reducing from 1 V to 1 × 10−4 V, respectively. Under lower electrical fields, the “instantaneous” jump and drop of current appeared respectively when the light was turned on and off. The durations of the “instantaneous” jump process decreased from 0.1826 s to 0.0736 s with the electrical field reducing from 1 V to 1 × 10−4 V, and durations of the “instantaneous” drop process decreased from 0.1588 s to 0.0698 s with the electrical field reducing from 1 V to 1 × 10−4 V, respectively. It was found that the change trends in the duration of “instantaneous” jump and drop stage with the electrical field are accord with the exponential decay function. From the exponential decay function, the durations of the “instantaneous” jump (Y1(0) = 0.0658 s) and drop (Y2(0) = 0.0681 s) were obtained in the case without an electrical field.