Surface nanopatterning of amorphous gallium oxide thin film for enhanced solar-blind photodetection

Abstract

Gallium oxide is an ultra-wide band gap semiconductor (E g > 4.4 eV), best suited intrinsically for the fabrication of solar-blind photodetectors. Apart from its crystalline phases, amorphous Ga2O3 based solar-blind photodetector offer simple and facile growth without the hassle of lattice matching and high temperatures for growth and annealing. However, they often suffer from long response times which hinders any practical use. Herein, we report a simple and cost-effective method to enhance the device performance of amorphous gallium oxide thin film photodetector by nanopatterning the surface using a broad and low energy Ar+ ion beam. The ripples formed on the surface of gallium oxide thin film lead to the formation of anisotropic conduction channels along with an increase in the surface defects. The defects introduced in the system act as recombination centers for the charge carriers bringing about a reduction in the decay time of the devices, even at zero-bias. The fall time of the rippled devices, therefore, reduces, making the devices faster by more than 15 times. This approach of surface modification of gallium oxide provides a one-step, low cost method to enhance the device performance of amorphous thin films which can help in the realization of next-generation optoelectronics.