engleski

PULSED LASER ABLATION OF GaAs USING DIFFERENT PULSE LENGTHS

Pulsed laser deposition offers a simple, convenient method of producing nano-scaled materials in which quantum confinement effects become significant and whose effects modify the material properties. Ablation using very short pulses has shown great promise in facilitating the growth of complex multi-element films with stoichiometries matching those of their parent materials. Gallium arsenide, a material important in the electronic and opto-electronic industries, has even greater potential if quantum confinement effects could be used to tune its material properties. PLD of GaAs in the nanosecond regime has already produced stoichiometric GaAs nanoparticles that exhibit finite size effects, provided the ablations are carried out in the presence of a background gas. The use of femtosecond-pulsed lasers provides the opportunity to study this system in a regime where the driving pulse terminates prior to the onset of electron-phonon coupling and the pulse’ s total energy is deposited before the target can react thermally. A recent study has shown that these ultra-short pulses produce stoichiometric crystallites in the 2– 20 nm range even in the absence of a background gas. This work investigates the effect of femtosecond and nanosecond laser pulse lengths on the ablation of GaAs.

pulsed laser deposition; nanodots; AFM

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