Optical investigation of Si nano-crystals in amorphous silicon matrix

Paper presents the comparative investigation of photoluminescence and Raman scattering spectra of pure amorphous silicon films and amorphous silicon films with different size Si nanocrystallites. Several PL bands in the IR spectral range with maxima at 0.90, 0.98, 1.14 and 1.36 eV have been revealed in studied samples. The 0.90-0.98 eV PL bands are attributed to the band tail luminescence in Si nano crystallites with the size of 15-20  nm. Concurrently, the 1.18 and 1.36 eV PL bands are connected, apparently, with radiative transition between quantum confined levels within Si QDs (size of 5-6 nm) embedded into a-Si matrix.