Highly sensitive AlGaN/GaN diode-based hydrogen sensors using platinum nanonetworks

AlGaN/GaN based diode sensors incorporating platinum nanonetworks for hydrogen sensing were demonstrated. Platinum nanonetworks with 2–3 nm diameter were synthesized by a simple solution phase method, and uniformly deposited on the semiconductor surface by spin-coating. The density of Pt nanonetworks was controlled by the number of the spin coating cycles. Selective-area deposition of the Pt nanonetworks was achieved by the standard photoresist lift-off technique. Compared to conventional Pt thin film diode sensors, the Pt nanonetwork sensor showed remarkably larger current change of 2.3 × 107% at 1 V for 4% H2 in N2 exposure, which resulted from the larger effective barrier height reduction due to the increased surface area of the Pt nanonetworks.