Platinum/porous GaN nanonetwork metal-semiconductor Schottky diode for room temperature hydrogen sensor

•A honeycomb GaN nanonetwork which is good for the absorption and diffusion of the hydrogen gas is firstly proposed and fabricated to a Schottky diode type hydrogen sensor.•Able to detect hydrogen gas diluted in air from 320 to 10,000 ppm.•Operation temperature is decreased from several 100 °C to room temperature.•No nanofabrication equipment is needed in the fabrication of nano-Schottky diode hydrogen sensor.

An in-plane electrically conductive honeycomb GaN nanonetwork grown by molecular beam epitaxy was used to fabricate a platinum (Pt)/porous GaN nanonetwork Schottky diode type hydrogen sensor. The Pt Schottky contact is a nanonetwork with typical width of 40 nm. Both the scanning electron microscopy image and current–voltage curve indicates that the Pt/porous GaN nanonetwork Schottky diode with barrier height of 0.497 eV and ideality factor of 38.5 is comprised of parallel nano-Schotttky diodes. The operating temperature of this Schottky diode hydrogen sensor on the porous GaN nanonetwork is successfully decreased to room temperature and it performs well in detecting hydrogen gas with various concentrations from 320 to 10,000 ppm.