CRITICAL CONDITIONS FOR ACHIEVING BLUE-LIGHT EMISSION FROM POROUS SILICON

By observing the luminescence micrographic images and measuring the de cay behaviors of photoluminescence spectra, it is found that the blue light-emitting porous silicon obtained by boiling water treatment beha ves very similarly to the red light-emitting sample. It is thus believ ed 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 nanos tructures, effective passivation of the internal surfaces of porous si licon layer, and keeping a mechanically strong Si skeleton. A theoreti cal estimation and the experiments show that the simultaneous fulfillm ent of these conditions is quite critical which explains the poor repr oducibility of achieving blue emission experimentally.