Ion beam synthesis and optical properties of semiconductor nanocrystals and quantum dots

摘要

Nanocrystals of semiconductor materials have been fabricated in SiO(sub 2) by ion implantation and subsequent thermal annealing. Strong red photoluminescence (PL) peaked around 750 nm has been observed in samples containing Si nanocrystals in SiO(sub 2). The Si nanocrystals in the samples with optimized PL intensities are a few nanometers in diameter. Difference in the absorption bandgap energies and the PL peak energies are discussed. Significant influence of implantation sequence on the formation of compound semiconductor nanocrystals are demonstrated with the GaAs in the SiO(sub 2) system. Optical absorption measurements show that Ga particles have already formed in the as-implanted stage if Ga is implanted first. A single surface phonon mode has been observed in the infrared reflectance measurement from samples containing GaAs nanocrystals.