Blue-Green Photoluminescence from Silicon Dioxide Films Containing Ge~+ Nanocrystals Formed under Conditions of High Hydrostatic Pressure Annealing

摘要

Photoluminescence (PL), Raman spectroscopy (RS) and Rutherford backscattering (RBS) were employed to the investigation of the Ge~+ ion implanted SiO_2 films annealed at atmospheric and hydrostatic pressure (P) of 12 kbar. Under excitation by 496 nm line of an Ar laser, for the films annealed at P = 12 kbar, Raman spectra show a peak at 300 cm~(-1) with the full width at half maximum (FWHM) of 6.5 cm~(-1). In the case of atmospheric pressure, RS peak at 296 cm~(-1) with FWHM of about 10 cm~(-1) was observed. RS spectra showed a resonance at excitation wavelength of ～496 nm. The resonant RS profile from the samples annealed under pressure were more sharp than that from the samples annealed under atmospheric conditions. RBS measurements showed no diffusion of Ge atoms during annealing under compression of 12 kbar up to annealing temperature (T_a) of 1130 ℃. After annealing under atmospheric pressure, a part of Ge atoms redistributed toward the top surface. It was found that hydrostatic pressure of 12 kbar during annealing leads to the redshift in PL spectra. Analyzing a dependence of FWHM on the nanocrystal dimensions and the model of three-dimensional quantum confinement of an electron-hole pair in the Ge nanocrustals we have come to conclusion that PL bands obtained are not connected with recombination of quantum confined electron and hole in silicon nanocrystals.