Broadband photodetectors based on layered 1D GaTe nanowires and 2D GaTe nanosheets

Abstract

Owing to their high surface-to-volume ratios and unique geometries, low dimensional materials such as 1D nanowires and 2D nanosheets have drawn considerable attention for developing high-performance broadband photodetectors (PDs). Gallium telluride (GaTe) is a p-type semiconductor with a direct band gap (1.65 eV) and exhibits high carrier mobility and long carrier lifetime. We report the comprehensive study of photoconductivity properties and photodetection mechanism of physical vapor transport (PVT) grown GaTe nanowires and GaTe nanosheets over a wide spectral range under different illumination power densities. The PDs were fabricated using two different GaTe nanostructures by focused-ion beam (FIB). The results demonstrated that both 1D and 2D PDs show broadband spectral photoresponses (UV to NIR, 325–808 nm), 1D PDs show a higher responsivity, detectivity, and sensitivity compared to those of 2D PDs. The photodetection mechanism was compared and discussed systematically. The reported photodetection performances are significantly higher than those of 1D and 2D GaTe PDs synthesized by CVD approach. The structural characterization reveals that the layer interfaces of GaTe nanosheet should be responsible for the charge carrier scatting centers during photodetection process. It is concluded that the carrier mobility of nanowire PD is significantly higher due to a lower scattering probability in the 1D nanostructure, further enhance their responsivity, detectivity, normalized gain, and sensitivity, respectively. The results suggest that the PVT grown GaTe 1D and 2D nanostructures may be promising materials for potential broadband photodetection applications.