Preparation and optical properties of InAs0.4P0.6nanocrystal alloy embedded in SiO₂thin films

InAs 0.4 P 0.6 nanocrystals with a size of 4.3-6.5 nm embedded in SiO 2 thin films were prepared by the radio-frequency magnetron co-sputtering technique. X-ray diffraction and Raman spectra strongly suggest the existence of InAs 0.4 P 0.6 nanocrystals in SiO 2 matrices. The size distribution of the nanocrystals was observed by transmission electron microscopy. The optical transmission spectra indicate that the optical absorption band edge of the composite thin films can be modulated in a very large wavelength range by changing the preparation conditions. The InAs 0.4 P 0.6 nanocrystals exhibit the behaviour of a direct bandgap. The marked blue shift of the optical absorption edge with respect to the bulk semiconductor can be explained by the quantum confinement effect.