SYNTHESIS OF GAAS NANOPARTICLES BY DIGITAL RADIO-FREQUENCY SPUTTERING

Nanometer-sized GaAs particles embedded in SiO2 were prepared by a digital rf-sputtering method, where GaAs and SiO2 targets were alternately sputtered in an Ar atmosphere. The GaAs deposition time was kept shorter than the time required to form a continuous layer. Transmission electron microscopy observations showed that the sizes of the GaAs particles can be controlled from 2 to 8 nm by changing the sputtering cycle time of the GaAs target. In spite of their small size, the GaAs particles have crystallinity similar to the target material without substrate heating or postannealing. The optical absorption spectra of the GaAs particles show a blue shift as large as 1.6 eV, corresponding to strong quantum confinement of electrons and holes. (C) 1995 American Institute of Physics.