Negative-capacitance and bulk photovoltaic phenomena in gallium nitride nanorods network

Abstract

An enhanced self-powered near-ultraviolet photodetection phenomenon was observed in epitaxial gallium nitride (GaN) nanorods network grown on an intermediate layer of N:GaN on a nitridated HfO 2 (N:HfO 2 )/ SiO 2 /p-Si substrate. The fabricated Au/GaN/N:GaN/N:HfO 2 /Ag heterostructure exhibited a giant change (OFF/ON ratio > 50 without applying any external electrical field) in its conductance when illuminated by a very weak (25 mW cm À2 ) near-UV monochromatic light with a low dark current (nearly 20 nA). The presented near-UV photodetector offers photoresponsivity of $2.4 mA W À1 at an applied voltage of 1 V.We observed an optically generated internal open circuit voltage of $155 mV and short circuit current $430 nA, which can be attributed to the quantum confinement of free charge carriers in the nanorod matrix. Interestingly, it also shows a negative capacitance after near-UV illumination. It has great potential as a self-powered UV photodetector and in metamaterial applications.

Low-Intensity Light Detection with a High Detectivity Using 2D-Sb2Se3 Nanoflakes on 1D-ZnO Nanorods as Heterojunction Photodetectors

“…However, the exact origin of NC in several optoelectronic devices remains undetermined and is debatable. The NC has been reported to enhance the overall optoelectronic properties of the heterostructure, − leading to the proposed 2D-Sb 2 Se 3 NFs/1D-ZnO NRs heterostructure to demonstrate the low-intensity detection of light at different wavelengths. Furthermore, a comparative study of similar types of PDs was performed, the results of which are listed in Table .…”