Application of a gateless AlGaN/GaN HEMT sensor for diesel soot particulate detection

Robert Sokolovskij, Hongze Zheng, Wenmao Li, Guangnan Zhou, Qing Wang, Guoqi Zhang, Hongyu Yu

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)


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.

Original languageEnglish
Article number130811
Pages (from-to)1-8
Number of pages8
JournalSensors and Actuators B: Chemical
Publication statusPublished - 2021


  • 2DEG
  • AlGaN/GaN
  • Diesel soot
  • HEMT
  • On-board diagnostics
  • Soot sensor


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