Porous Silicon Nanowire Arrays for Reversible Optical Gas Sensing

Abstract

Porous silicon nanowire arrays are shown to be used for optical detection of molecular oxygen (O 2 ). The samples are produced by metal assisted chemical etching of heavily boron‐doped wafers of crystalline silicon. It is found that the photoluminescence signal from porous silicon nanowires quenched in O 2 ambience but restored again in N 2 atmosphere, which repeated in several cycles. Electron paramagnetic resonance data demonstrate that number of silicon dangling bonds (Pb‐center) increases after O 2 adsorption, but then drops in vacuum. The experimental results are explained by a microscopic model taking into account the reversible charging/recharging of surface defects (Pb‐centers) due to the oxygen adsorption/desorption. The obtained results indicate that porous silicon nanowires are prospective for applications as reversible optical gas sensor.