Photoluminescence spectra of high temperature vacuum annealed porous silicon

The photoluminescence (PL) spectra of porous silicon layers annealed for 15 to 180 sec in vacuum at temperatures above 800/spl deg/C are presented. The experimental spectra consist of two main PL bands at 1.8 eV and 2.2 eV. The 2.2 eV band is independent of the annealing time and origins from silicon nanocrystallites. The 1.8 eV band decreases with increasing annealing time following second-order kinetics, typical for silicon dihydride decomposition.