Effect of thermal annealing and surface coverage on porous silicon photoluminescence

The effect of thermal annealing and surface coverage on porous silicon photoluminescence was studied in situ in an ultrahigh vacuum chamber. These investigations correlated simultaneously temperature, surface coverage, and photoluminescence intensity. The surface coverage was monitored using transmission Fourier transform infrared spectroscopy. The results demonstrated that the photoluminescence could not be defined only according to the presence of SiH2 surface species. Likewise, the disappearance of the photoluminescence versus thermal annealing did not scale directly with H2 desorption from SiH2 species. The loss of photoluminescence versus thermal annealing was attributed to surface structural changes or the production of surface states which provide pathways for nonradiative recombination.