Nanoporous silicon metal-semiconductor-metal visible light photodetector

Abstract

In this research, we present the study on the application of nanoporous silicon for optoelectronic device which called nanoporous silicon metal-semiconductor-metal (MSM) visible light photodetector in this paper. This device was fabricated on nanoporous silicon layer which was formed by electrochemical etching of silicon wafer in hydrofluoric acid solution under various anodization condition such as the resistivity of silicon wafer, current density, concentration of hydrofluoric acid solution and anodization time. The structure of this device has two square Al/nanoporous silicon Schottky-barrier junctions on the silicon substrate and the electrode spacing is 500 µm. The experiment will study on photoresponse and responsetime of nanoporous silicon MSM photodetector which was fabricated on various porosity of nanoporous silicon layer. It is found that when devices fabricated on higher porosity nanoporous silicon layer, the photoresponse of device will expand toward the short-wavelength and bandwidth of spectum response will cover visible light. In addition, it is found that responsetime of device decreases.