Ion beam modification of porous silicon using high energy Au+7 ions and its impact on photoluminescence spectra

This paper presents investigation of impact of high-energy ion-irradiation on properties of light emitting porous silicon (PS) through photoluminescence (PL) spectroscopy. Irradiation was performed with 100 MeV Au+7 ions from a pelletron accelerator at ion doses in 10(10)-10(14)cm(-2) range. The effect was associated with a blueshift (similar to 40 nm) and an enhancement of the PL intensity, in general. The efficiency and stability of PL with respect to ambients was seen to be relatively improved. The PL properties of PS were found to be stable against low to medium dose irradiation (<10(13) cm(-2)), whereas, higher dose led to further degradation of the optical properties. The effects have been explained in terms of a decrease in the non-radiative recombination probability of electron-hole pairs due to chemical restructuring of the surface and a reduced crystallite size as a result of irradiation. (C) 2003 Elsevier B.V. All rights reserved.