Persistent Photoconductivity in Zinc Tin Nitride*

Zinc Tin Nitride (ZnSnN₂) is a semiconductor material that has shown promising qualities for solar cell technologies. In the search for efficient solar cell materials, Zinc Tin Nitride is a particularly favorable candidate as it is composed of non-toxic, earth abundant elements. Photoconductivity studies revealed that when optically excited, Zinc Tin Nitride exhibits an increase in electrical conductance with increasing intensities of incident light (red LED 660 nm). With prolonged exposure, the photoconductance of the material plateaued – approaching peak photoconductance at a given light intensity. After the light source was removed, a slow decay in photoconductance was observed which is consistent with persistent photoconductivity (PPC). The decay was well described by a stretched exponential function. These results suggest the prevalence of defect states, such as traps and recombination levels, within the material’s band gap. The temperature dependence of this behavior is being investigated to further elucidate the nature of the defect states involved.