Improved H₂ detection performance of GaN sensor with Pt/Sulfide treatment of porous active layer prepared by metal electroless etching

High-performance chemiresistor gas sensor made of sulfide porous GaN decorated with Pt nanoparticles, which shows tunable sensor response and enhanced sensitivity. The fabricated gas sensors show detection of H₂ down to 30 ppm at 23 °C after sulfide treatment and Pt decorated porous GaN. The response time and recovery time were equal to 47 s and 113 s, respectively. Density functional theory simulations were used to support the detection mechanism based on sulfide treatment. Adsorption energy calculations showed that H adsorption energy is lowered by the simultaneous presence of S and Pt on the GaN (0001) surface. The density of states (DOS) calculations revealed possibility of bond strengthening when Pt and S is adsorbed on GaN surface along with H, arising from the hybridization of d and p orbitals of Pt and S with that of H 1s orbitals.