The effect of UV irradiation on temperature dependence of photoluminescence and photoacoustic response in porous silicon

The influence of UV irradiation on temperature dependence of the integral intensity of luminescence I-lum(T) in porous silicon was studied. It was found that, if luminescence decays with temperature nonmonotonically, the peak of I-lum(T) shifts toward higher temperatures as the exciting radiation density increases. Under UV irradiation, the function I-lum(T) becomes monotonically decreasing. If the function I-lum(T) is initially monotonically decreasing, UV preirradiation changes the emission spectrum and accelerates temperature quenching of the red-orange emission band. The variation of the amplitude of the pulsed photoacoustic response with UV irradiation dose was studied. The dependence found is explained by the removal of foreign inclusions from the developed surface of porous silicon. An energy level diagram that makes it possible to explain the behavior of I-lum(T) is suggested. It is noted that the shape of the function I-lum(T) can be used as a test whereby the contributions from dissimilar oscillators to the red-orange emission band are estimated. (C) 2001 MAIK "Nauka/Interperiodica".