Interface and wetting layer effect on the catalyst-free nucleation and growth of GaN nanowires

A study was conducted to investigates the effect of interface and wetting layer on the catalyst-free plasma-assisted MBE (PAMBE) growth of GaN nanowires (NWs) using high-resolution transmission electron microscopy (HRTEM). GaN Nws were grown at 780°C by PAMBE without the use of catalysts on clean Si(111) and oxidized Si(100) substrates. An amopphous silicon nitride layer was formed by nitridation of the Si substrate in the initial stages of deposition. A new GaN clusters continue to form during deposition even after the interface layer is formed, because of random nucleation of GaN NWs. It was found the the thickness of the interface layer was increasee during GaN deposition due to GaN cluster migration or by lateral side nitridation o Si small clusters and wires. The growth of high-crystalline quality vertical GaN-NWs is found on amporphous oxidized silicon substrates.