Temperature Dependence of Photoluminescence in Porous Silicon

Porous silicon samples have been successfully prepared by elect rochemical etching technique, which show intense photoluminescence (PL) in the visible wave-length region. The measurements of the temperature dependence of PL in porous silicon show that the wavelength of the luminescent peak shifts to the blue and the PL band width does not change as the temperature of the sample increases over a wide range. The intensities of PL are measured as a function of temperature showing the confined exciton recombination behaviour, and the activation energies of 68.6 and 205meV of the excitons have been obtained for the low temperature and high temperature regions, respectively. The results suggest that the PL in porous silicon is due to the radiative recombination in a quantum wire system.