Cluster Generation Under Pulsed Laser Ablation Of Compound Semiconductors

TL;DR

This study compares laser ablation of zinc oxide and indium phosphide, revealing differences in cluster composition and formation mechanisms, with implications for material processing and nanocluster synthesis.

Contribution

It provides experimental insights into the distinct cluster generation behaviors of ZnO and InP during pulsed laser ablation, highlighting the effects of vaporization and plume dynamics.

Findings

ZnO produces mainly stoichiometric clusters

InP generates indium-rich clusters with In4P as a magic cluster

Plume conditions favor stoichiometric cluster formation in ZnO ablation

Abstract

A comparative experimental study of pulsed laser ablation in vacuum of two binary semiconductors, zinc oxide and indium phosphide, has been performed using IR-and visible laser pulses with particular attention to cluster generation. Neutral and cationic Zn\_n O\_m and In\_n P\_m particles of various stoichiometry have been produced and investigated by time-of-flight mass spectrometry. At ZnO ablation, large cationic (n>9) and all neutral clusters are mainly stoichiometric in the ablation plume. In contrast, indium phosphide clusters are strongly indium-rich with In\_4 P being a magic cluster. Analysis of the plume composition upon laser exposure has revealed congruent vaporization of ZnO and a disproportionate loss of phosphorus by the irradiated InP surface. Plume expansion conditions under ZnO ablation are shown to be favourable for stoichiometric cluster formation. A delayed vaporization of phosphorus under InP ablation has been observed that results in generation of off-stoichiometric clusters.