Preparation and optical properties of InAs0.4P0.6 nanocrystal alloy embedded in SiO2 thin films

InAs0.4P0.6 nanocrystals with a size of 4.3-6.5 nm embedded in SiO2 thin fi lms were prepared by the radio-frequency magnetron co-sputtering technique. X-ray diffraction and Raman spectra strongly suggest the existence of InAs 0.4P0.6 nanocrystals in SiO2 matrices. The size distribution of the nanocry stals was observed by transmission electron microscopy. The optical transmi ssion spectra indicate that the optical absorption band edge of the composi te thin films can be modulated in a very large wavelength range by changing the preparation conditions. The InAs0.4P0.6 nanocrystals exhibit the behav iour of a direct bandgap. The marked blue shift of the optical absorption e dge with respect to the bulk semiconductor can be explained by the quantum confinement effect.