Fabrication of Nanopillars Comprised of InGaN/GaN Multiple Quantum Wells by Focused Ion Beam Milling

Abstract

The focused ion beam direct-written InGaN/GaN multiple-quantum-well nanopillars display strong cathodoluminescence emission blue-shifted by 35 meV compared with that of the as-grown wafer. With the removal of ion-irradiation-damage layers, the emission intensity even increased by a factor of 15. The ion beam induced nanopillar swelling was deliberately enhanced by tuning the beam condition, and the swollen volume can also be easily removed by wet-etching using KOH solution. The swelling behavior of an InGaN/GaN nanopillar under focused ion beam milling is found to play an important rule in reducing pillar size.