We report on the enhanced hydrogen sensing characteristics of surface-etched Pt Schottky diodes fabricated on semipolar (11 (2) over bar2) GaN films using photo-electrochemical wet etching. The surface-etched Pt Schottky diodes showed a rapid sensing response to 4% hydrogen, as well as a full recovery to their initial current level after removing the hydrogen from the ambient. They also demonstrated stable and reproducible current changes with a reasonable linearity in response to H-2 concentrations of 0.5 similar to 4% in increments of 0.5%. The hydrogen sensitivity of Pt Schottky diodes on semipolar (11 (2) over bar2) GaN could therefore be improved by incorporating surface etching on the Schottky contact area using KOH solutions. This rough surface is expected to improve hydrogen detection sensitivity due to the presence of more available adsorption sites, resulting in effective variations of the Schottky barrier height. (C) 2016 The Electrochemical Society. All rights reserved.