Luminescence of heteroepitaxial silicon films on sapphire

Low-temperature (4.2 K) photoluminescence of silicon on sapphire films with different thicknesses has been investigated. The experiments show that the common form of luminescence spectra in the energy range from 0.7 to 1.15 e V (the number of wide bands in the spectra, their shape, the energy positio n, the intensity) is strongly dependent oil the thickness pf the films. Som e of these bands can be definitely assigned to radiative recombination at d islocations. It is found that in the luminescence spectra of silicon on sap phire films impurity-bound emission, bands are shifted relative to their po sition in single-crystal bulk silicon. The residual compressive stress in s ilicon on sapphire films is estimated, using the photoluminescence method.