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 (O2). 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 O2 ambience but restored again in N2 atmosphere, which repeated in several cycles. Electron paramagnetic resonance data demonstrate that number of silicon dangling bonds (Pb‐center) increases after O2 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.