Formation of GaAs nanocrystals by laser ablation

The pulsed laser ablation method has been used to form GaAs nanocrystals. A quadrupled frequency Nd:yttrium-aluminum-garnet laser beam is focused onto a GaAs single crystal target, and a nitrogen flowing gas is sent at the neighborhood of the target in order to transfer in an ethanol bath, the nanoparticles grown in gas phase. The composition of the particles is close to stoichiometry and transmission electron microscopy analyses highlight zinc-blende GaAs nanocrystals with a rather well defined size: 5-8 nm diameter. The low temperature photoluminescence and photoluminescence excitation spectra show quantum confinement of about 870 meV via an emission band in the visible range (500-560 nm) for the GaAs nanocrystals produced by laser ablation without any postannealing treatment. (C) 2001 American Institute of Physics.