Differences in hydrogen absorption over Pd and Pt functionalized CVD-grown GaN nanowires

Abstract

In this study, we report the differences in hydrogen (H2) absorption properties of platinum (Pt) and palladium (Pd) functionalized gallium nitride (GaN) nanowires via gas sensing studies. GaN nanowires of ∼25−200 nm diameter and ∼50−75 μm length are grown uniformly over large area (10×10 mm2) using Au assisted chemical vapour deposition technique. The nanowires are grown at 900 for 2 h using gallium (Ga) as source material and ammonia (NH3) as the reacting gas. The nanowires are functionalized with Pd and Pt nanoclusters using solution technique. H2 absorption by these functionalized nanowires which is manifested as gas sensing response is compared in the temperature range of 50–200. The role of surface kinetics in Pd and Pt is shown to be responsible for the difference in the sensor response.