Hydrogen gas ppb-level detection based on AlGaN/GaN high electron mobility transistor with 2.0 nm thick Pt gate layer

Abstract

In this work, ppb-level H2 gas detection based on the Pt-gated AlGaN/GaN high electron mobility transistor device was obtained through minimizing the H atom diffusion distance by the utilization of a critical Pt gate thickness of ∼2.0 nm. The Ids-Vds curves show that the device exhibits a pinch-off characteristic with an on-to-off ratio of about four orders of magnitude. High response (775% at 100 ppm, 25.4% at 1 ppm) and short response times (2.5 s at 10 000 ppm) are observed at 150 °C. Particularly, the device has a response to trace H2 gas as low as 60 ppb, indicating a small low limit of detection (LOD) < 60 ppb. Its capability to detect very low H2 gas together with a high response makes it promising for trace H2 gas detection such as exhale breath analysis. Moreover, it is found that the H2 detection range depends on the operating temperature, which is useful in real applications that require various H2 gas detection ranges.