Effect of substrate on photo-induced persistent photoconductivity in InAs nanowires

The thermal conduction by the difference in the substrate of InAs nanowires (NWs) was investigated by determining the local temperature using Raman spectroscopy as an optical method. The optoelectric characteristics of the supported and suspended InAs nanowires were also investigated. The change in the current with the laser power produced a characteristic profile depending on the InAs nanowire configuration. The persistent photoconductivity (PPC) effect in the InAs nanowires has not been previously studied in detail despite its importance for the material photoresponse. This report presents a study of the PPC effect and the underlying mechanism. The correlation between the PPC effect and the thermal conduction by the substrate-induced carrier redistribution in the InAs nanowires is highlighted. In addition, a unique PPC effect associated with a specific device structure is studied. Our results can enable novel functionalities for InAs-based optoelectric applications in the future.