Alteration of structural and optical properties in quaternary Al0.1In0.1Ga0.8N films using ultraviolet assisted photo-electrochemical etching route

Structural and optical properties of quaternary Al0.1In0.1Ga0.8N films, subjected to photo-electrochemical etching in different concentrations of potassium hydroxide (KOH) solution under ultraviolet (UV) illumination have been investigated. A co-relationship between the structural and optical properties has been discussed in association with the pore formation mechanism. Results showed formation of vacancies as localized states in the porous films, which increased Urbach energy and decreased optical band gap (E-g). An optimum optical characteristic has been perceived by the film etched in 4% KOH due to acquisition of the highest photoluminescence (PL) emission intensity, the largest Eg value, as well as the largest stress and strain relaxation in the film as compared to the non-porous film. (C) 2015 Elsevier B.V. All rights reserved.