A particulate matter micro-sensor for automotive exhaust systems based on a gateless wide-bandgap AlGaN/GaN high electron mobility transistor was developed and tested. Soot particles were generated by a laminar diesel flame and characterized with Raman spectroscopy, thermogravimetric analysis and scanning electron microscopy. Particle adsorption at the rate of 0.25 µg/min on the sensor surface resulted in 5.52% sensing response after 20 s and large signal variation of 4.44 mA, indicating fast response time. Saturated response of 34.72% (27.94 mA) was obtained after 10 min of deposition. The sensitivity towards soot is attributed to the modulation of the two-dimensional electron gas density by charged particles on the sensing surface. After soot deposition, the sensor was successfully regenerated by thermal oxidation of the carbonaceous particles at 600 °C. The sensing response remained unchanged post-regeneration indicating high temperature stability and harsh environment operation compatibility of the demonstrated GaN-based sensor. Nevertheless, interconnect metal optimization is still required to mitigate high-temperature interdiffusion.

开发并测试了一种基于无栅极宽带隙 AlGaN/GaN 高电子迁移率晶体管的汽车排气系统颗粒物微传感器。烟尘颗粒由层流柴油火焰产生，并用拉曼光谱、热重分析和扫描电子显微镜进行表征。传感器表面以 0.25 µg/min 的速率吸附颗粒，20 秒后传感响应为 5.52%，信号变化大为 4.44 mA，表明响应时间快。沉积 10 分钟后获得 34.72% (27.94 mA) 的饱和响应。对烟尘的敏感性归因于传感表面上的带电粒子对二维电子气密度的调制。烟尘沉积后，通过在 600 °C 下对碳质颗粒进行热氧化，成功地再生了传感器。再生后传感响应保持不变，表明所展示的 GaN 基传感器具有高温稳定性和恶劣环境操作兼容性。尽管如此，仍然需要互连金属优化来减轻高温相互扩散。