Mechanism of PLD using Ga-Zn Liquid Alloy Target for Zn-doped GaN Growth

The pulsed laser deposition (PLD) of GaN with Zn-dopant was closely investigated. The particular emphasis was placed on the PLD target consisting of liquid alloy of Ga and Zn. Throughout the work, an ArF excimer laser (193-nm wavelength and 20-ns duration) was used. Both Ga and Zn atoms could be simultaneously ablated from the alloy target, and ablation ratio of Zn/Ga was found to markedly depend on the laser fluence. Namely, lower laser fluence led to less Ga content in the ablated particles, and with high laser fluences the congruent ablation developed. Image of plume emission revealed that plume dynamics of Ga and Zn is very close to each other. Zn-doping to the GaN by the PLD method is carried out using the liquid Ga-Zn alloy target in N2 ambient. PL spectrum of the film shows the clear evidence of Zn incorporation to the GaN film.