Porous GaN Submicron Rods for Gas Sensor with High Sensitivity and Excellent Stability at High Temperature

Highly porous GaN submicron rods have been synthesized successfully by a facile hydrothermal method and heat treatment under controlled atmosphere. The morphology and size of the hydrothermal products are tailorable by adjusting the concentration of precursor solutions. Upon calcination in air, the nanorod-assembled GaOOH submicron rods are converted into bundlelike Ga₂O₃ and into porous GaN submicron rods under an ammonia flow. Gas-sensing characterization demonstrates that the sensors based on porous GaN exhibit high sensitivity and fast response to ethanol vapor, as well as excellent stability and reliability at high temperature. The highly porous GaN submicron rods with a large specific surface area, small grain size, and high length-to-diameter ratio show better response to ethanol. A possible sensing enhancement mechanism is also proposed. This study provides a promising route for the novel synthesis of GaN submicron rods for high-performance gas sensors.