Fabrication and properties of nanoporous GaN films

Abstract

Nanopore arrays with pore diameters of approximately 75nm were fabricated in GaN films by inductively coupled plasma etching using anodic aluminum oxide (AAO) films as etch masks. Nanoporous AAO films were formed on the GaN surface by evaporating an Al film onto a GaN epilayer and subsequently anodizing the aluminum. To minimize plasma-induced damage, the template was exposed to CF4-based plasma conditions. Scanning electron microscopy analysis shows that the diameter and the periodicity of the nanopores in the GaN were directly transferred from the original anodic alumina template. The pore diameter in the AAO film can be easily controlled by tuning the anodization conditions. Atomic force microscopy, photoluminescence, and micro-Raman techniques were employed to assess the etched GaN nanopore surface. This cost-effective, nonlithographic method to produce nano-patterned GaN templates is expected to be useful for growth and fabrication of nitride-based nanostructures and photonic band gap materials.

High Optical Quality Nanoporous GaN Prepared by Photoelectrochemical Etching

“…15 Photoelectrochemical etching would be more suitable as a cost effective method to produce high-density nanopores with pore size < 100 nm. The pore size, etching depth or the transverse dimension of the pores can be easily controlled by varying the etching/anodization conditions.…”

Fabrication of p-type porous GaN on silicon and epitaxial GaN

“…3 The formation of p-type porous GaN is particularly relevant 4 for the fabrication of junctions and active regions for GaN-based LEDs with improved light extraction efficiency and external quantum efficiencies by gradation of the effective refractive index. 5 Porous GaN has been typically fabricated by (photo)electrochemical and chemical etching methods, [6][7][8][9] predominantly a top-down etching of epitaxial GaN, giving textured surfaces as a result of pore coalescence and variations in etch rates for extended etching times. A range of nanoscale III-N materials 10,11 in arrays and assemblies spanning emission from the blue to red regions of the visible spectrum, 12 and white light emitting light emitting devices and multi quantum wells have also been realized.…”

Window-assisted nanosphere lithography for vacuum micro-nano-electronics

“…and has been demonstrated to be well suited to fabricate nanoholes, [13][14][15] metallic nanomesh electrodes, 16,17 or silicon, [18][19][20] noble metal, 21 cobalt, 22,23 and gallium nitride nanorod arrays. 24 The function of NSL relies on templates for nanostructure patterning. Self-assembled polystyrene (PS) nanosphere monolayers are used commonly as templates of NSL.…”