A method for ensuring the structural integrity of III-nitride opto-electronic or opto-mechanical air-gap nano-structured devices, comprising (a) performing ion beam implantation in a region of the III-nitride opto-electronic and opto-mechanical air-gap nano-structured device, wherein the milling significantly locally modifies a material property in the region to provide the structural integrity; and (b) performing a band-gap selective photo-electro-chemical (PEC) etch on the III-nitride opto-electronic and opto-mechanical air-gap nano-structured device. The method can be used to fabricate distributed Bragg reflectors or photonic crystals, for example. The method also comprises the suitable design of distributed Bragg reflector (DBR) structures for the PEC etching and the ion-beam treatment, the suitable design of photonic crystal distributed Bragg reflector (PCDBR) structures for PEC etching and the ion-beam treatment, the suitable placement of protection layers to prevent the ion-beam damage to optical activity and PEC etch selectivity, and a suitable annealing treatment for curing the material quality after the ion-beam treatment.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
 This invention was made with Government support under Grant No. DE-FC26-01NT41203 awarded by the Department of Energy. The Government has certain rights in this invention.