Suspended AlGaN/GaN membrane devices with recessed open gate areas for ultra-low-power air quality monitoring

We have developed a novel gas sensor platform for ultra-low-power air quality monitoring based on suspended AlGaN/GaN membranes fabricated on 8 inch Si(111) wafers. Due to precise sensing area recessing, the device shows excellent sensitivity to NO₂, a major air pollutant, allowing the detection of single-ppb steps in the gas concentration. A key feature of the device is the small interference from humidity. We show extension of the platform to NH₃, H₂ and CO₂ detection.