Fabrication and Characterization of Uniform Quantum Size Porous Silicon

Porous silicon layer microstructure is sensitive to many parameters which need to be controlled during etching. These include not only anodization time, current density and applied potential but also electrolyte composition. Careful control these parameters will yield excellent reproducibility from run to run. In this paper we outline the advances in porous silicon surface quality and uniformity by recent techniques that have made the production of uniformly sized silicon nanocrystallites possible. In this work we used the oxidant H2O2 in the wet etching bath, with a high etching current. The resulting technique greatly improves the uniformity of the porous surface, producing a very thin layer of porous silicon. This is a significant improvement to the previous method. The result of a combined study of FTIR spectra and photoluminescence show that both quantum confinement and surface passivation are responsible of blue shift of the luminescence peak.