Low operating temperature NO gas sensors based hydrogen peroxide treated GaN nanorods

Abstract

Abstract In recent days, surface treatment strategies have employed to enhance the active sites for chemisorption of gas molecules in gas sensors. In this work, the simple and effective hydrogen peroxide (H2O2) treatment is used to enhance the active sites on the surface of gallium nitride (GaN) nanorods (NRs) for nitric oxide (NO) gas detection. The surface treatment was carried out by immersing the GaN NRs into a hydrogen peroxide (H2O2) solution at different temperatures for 10 min. The X-ray photoelectron spectroscopy (XPS) is used to find the physicochemical properties of GaN NRs. XPS studies revealed that the active sites (O2 species) on GaN NRs were increased by H2O2 treatment. NO gas sensing measurements revealed that response of the H2O2 treated GaN NRs enhanced by 4-times than that of pristine GaN NRs to 100 ppm of NO gas concentration at 50 °C. Further, H2O2 treated GaN NRs exhibited high response under UV illuminations (λ = 382 nm, P = 1.45 mW/cm2) compared to dark conditions. Under UV illumination, the H2O2 treated GaN NRs generated a large amount of electron-hole pairs, indicating additional defect states on the surface of GaN NRs induced by the H2O2 treatment and these are accountable for the high NO gas response.