Critical conditions for achieving blue light emission from porous silicon

Abstract

By observing the luminescence micrographic images and measuring the decay behaviors of photoluminescence spectra, it is found that the blue light-emitting porous silicon obtained by boiling water treatment behaves very similarly to the red light-emitting sample. It is thus believed that the blue light emission is originated from the porous silicon skeleton rather than impurity contaminations. The achievement of blue light emission requires the proper control of the size of the Si nanostructures, effective passivation of the internal surfaces of porous silicon layer, and keeping a mechanically strong Si skeleton. A theoretical estimation and the experiments show that the simultaneous fulfillment of these conditions is quite critical, which explains the poor reproducibility of achieving blue emission experimentally.