Thermally Phase-Transformed In2Se3 Nanowires for Highly Sensitive Photodetectors

Abstract

The photoresponse characteristics of In2Se3 nanowire photodetectors with the -phase and -phase structures are investigated. The as-grown -phase In2Se3 nanowires by the vapor-liquid-solid technique are phase-transformed to the -phase nanowires by thermal annealing. The photoresponse performances of the -phase and -phase In2Se3 nanowire photodetectors are characterized over a wide range of wavelengths (300-900 nm). The phase of the nanowires is analyzed using a high-resolution transmission microscopy equipped with energy dispersive X-ray spectroscopy and X-ray diffraction. The electrical conductivity and photoresponse characteristics are significantly enhanced in the -phase due to smaller bandgap structure compared to the -phase nanowires. The spectral responsivities of the -phase devices are 200 times larger than those of the -phase devices. The superior performance of the thermally phase-transformed In2Se3 nanowire devices offers an avenue to develop highly sensitive photodetector applications.