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 ne ighborhood of the target in order to transfer in an ethanol bath, the nanop articles grown in gas phase. The composition of the particles is close to s toichiometry and transmission electron microscopy analyses highlight zinc-b lende GaAs nanocrystals with a rather well defined size: 5-8 nm diameter. T he low temperature photoluminescence and photoluminescence excitation spect ra show quantum confinement of about 870 meV via an emission band in the vi sible range (500-560 nm) for the GaAs nanocrystals produced by laser ablati on without any postannealing treatment. (C) 2001 American Institute of Phys ics.