Formation of silicon nanocrystals with preferred (100) orientation in amorphous Si:H films grown on glass substrates and exposed to nanosecond pulses of ultraviolet radiation

Using Raman scattering, it was ascertained that silicon nanocrystals with sizes exceeding 2 nm are formed in amorphous silicon films exposed to nanosecond ultraviolet laser radiation with energy densities ranging from 75 to 150 mJ/cm(2); it is shown that these nanocrystals have sizes no smaller than 2 nm and have preferred (100) orientation along the normal to the film surface. In a system of mutually oriented Si nanocrystals, anisotropic behavior of the Raman scattering intensity was experimentally detected in various polarization configurations, which made it possible to determine the volume fraction of oriented nanocrystals. The orientational effect is presumably caused by both the macroscopic fields of elastic stresses in the film and the local fields of elastic stresses around the nanocrystals. (C) 2002 MAIK "Nauka / Interperiodica".