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 i ntensity of luminescence I-lum(T) in porous silicon was studied. It was fou nd that, if luminescence decays with temperature nonmonotonically, the peak of I-lum(T) shifts toward higher temperatures as the exciting radiation de nsity increases. Under UV irradiation, the function I-lum(T) becomes monoto nically decreasing. If the function I-lum(T) is initially monotonically dec reasing, UV preirradiation changes the emission spectrum and accelerates te mperature quenching of the red-orange emission band. The variation of the a mplitude of the pulsed photoacoustic response with UV irradiation dose was studied. The dependence found is explained by the removal of foreign inclus ions 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 whe reby the contributions from dissimilar oscillators to the red-orange emissi on band are estimated. (C) 2001 MAIK "Nauka/Interperiodica".