Porous Silicon Nanowire Arrays for Reversible Optical Gas Sensing

摘要

Porous silicon nanowire arrays are shown to be used for optical detection ofrnmolecular oxygen (O_2). The samples are produced by metal assisted chemicalrnetching of heavily boron-doped wafers of crystalline silicon. It is found thatrnthe photoluminescence signal from porous silicon nanowires quenched in O_2rnambience but restored again in N_2 atmosphere, which repeated in severalrncycles. Electron paramagnetic resonance data demonstrate that number ofrnsilicon dangling bonds (Pb-center) increases after O_2 adsorption, but thenrndrops in vacuum. The experimental results are explained by a microscopicrnmodel taking into account the reversible charging/recharging of surfacerndefects (Pb-centers) due to the oxygen adsorption/desorption. The obtainedrnresults indicate that porous silicon nanowires are prospective for applicationsrnas reversible optical gas sensor.