Photoelectrochemical etching of p -type GaN heterostructures

Abstract

We have developed a method for photoelectrochemical etching of p -type semiconductors, including GaN, that relies on the built-in bandbending already inherent to optical devices. Electron-hole pairs are generated by filtered light in a buried small bandgap layer, and a pn junction separates the charge. Electrons are sent into the n -type layer, where they are extracted, and holes to the surface, where they participate in etching reactions. This technique is rapid and inexpensive, and it requires no applied bias or elevated temperatures. This technique has widespread applications to GaN optical devices where ion-damage-free etching or wide tunability of etch parameters is desired. © 2009 American Institute of Physics.