Quality-enhanced GaN epitaxial films grown on (La, Sr) (Al, Ta)O3 substrates by pulsed laser deposition

Abstract

High-quality GaN films have been epitaxially grown on (La, Sr) (Al, Ta)O3(LSAT) substrates by pulsed laser deposition (PLD) with an in-plane alignment of GaN[112¯0]//LSAT[11¯0]. The as-grown ~300-nm-thick GaN films grown at 450°C show very flat surface with a root-mean-square surface roughness of 0.9nm, full-width at half-maximums for GaN(0002) and GaN(101¯2) X-ray rocking curves of 0.06° and 0.10°, respectively, and sharp and abrupt GaN/LSAT hetero-interfaces. Moreover, with the increase in growth temperature, the surface morphology, crystalline quality and interfacial property of as-grown GaN films are deteriorated gradually. The high-quality GaN films grown on LSAT substrates by PLD are of great importance for the preparation of GaN-based devices.