Ultra Low Power Mass-Producible Gas Sensor Based on Efficient Self-Heated GaN Nanorods

This paper reports the fabrication and characterization of GaN nanorods (NRs) with a bottom contact and freestanding top contact. A top-down approach was adopted to produce an ordered array of high surface-to-volume NRs elements of GaN for gas sensing applications [1]. The GaN NRs were then used both as sensitive beams for conductometric gas sensing and as nanosized heating elements to activate their own response to gases (self-heating). GaN NRs with a diameter of 300 nm in arbitrarily large and regular arrays of 1 × 1, 3 × 3, 9 × 10 were fabricated. With power levels in the range of microwatts, these structures reach highly enough temperatures to develop a gas sensing response towards ethanol. In summary, this is one of the first systems showing efficient self-heating that can be produced using conventional microelectronic processing at a wafer scale.