Ti-mask Selective-Area Growth of GaN by RF-Plasma-Assisted Molecular-Beam Epitaxy for Fabricating Regularly Arranged InGaN/GaN Nanocolumns

Abstract

The Ti-mask selective-area growth (SAG) of GaN on Ti-nanohole-patterned GaN templates by rf-plasma-assisted molecular-beam epitaxy was employed to demonstrate the fabrication of regularly arranged InGaN/GaN nanocolumns. The SAG of GaN nanocolumns strongly depended on the growth temperature (Tg); at Tg below 900 °C, no SAG occurred, but above 900 °C, SAG occurred. However, an excessive increase in Tg to above 900 °C at a nitrogen flow rate (QN2) of 3.5 sccm brought about increased inhomogeneity in the nanocolumn shape. Upon reducing QN2 from 3.5 to 1 sccm, uniform nanocolumn arrays were successfully grown around the critical temperature of 900 °C.