Effect of resistivity and current density on photoluminescence in porous silicon produced at low HF concentration

An experimental study of the intensity of photoluminescence (PL) of porous silicon prepared from an anodic dissolution of Si at low HF concentration (12.5%) of p-type (100) 0.01, 1 and 10 Ohm cm substrates as a function of substrate resistivity and etching current density has been performed. Based on the experimental results a photoluminescence efficiency diagram is proposed. Etching of p(+)-type silicon samples without light illumination produces PSi layers whose PL spectra show interference fringes. Comparison of the fringes in PL and in light reflectivity demonstrates unambiguously that they originate from the interference of the light reflected at the PSi/ bulk Si interface and depend on the thickness of the PSi layer. The intensity and frequency of the interference fringes are found to be strongly dependent on the anodization current. Implications of PSi layer fabrication at low HF concentration are discussed. (C) 1998 American Institute of Physics. [S0021-8979(98)06623- 7].