OPTICAL INVESTIGATION OF GROWTH MODE OF GE THIN-FILMS ON SI(110) SUBSTRATES

A unique growth mode of Ge on Si(110) substrates was clarified by phot oluminescence (PL) spectroscopy. A spectral redshift and an increase o f the relative no-phonon intensity were found for PL from the two-dime nsional Ge layer on Si(110) compared to that on Si(100). These results likely arise from nonuniformity in the Ge layer thickness owing to th e step-bunched Si(110) surface and resultant exciton localization. The two-dimensional to three-dimensional growth mode changeover was obser ved as evidenced by emergence of broad PL from Ge islands. In contrast to Ge on Si(100) PL from the wetting layer was found to show continuo us redshift with increasing Ge coverage even after Ge island formation . (C) 1997 American Institute of Physics.