MoS2-decorated graphene gate AlGaN/GaN/AlN HEMTs for highly selective hydrogen gas sensor

Purpose Hydrogen is widely acknowledged as a potentially useful clean energy carrier. A high degree of selectivity in sensing systems are required to ensure its safe deployment. This research aims to propose a H2 gas sensor that demonstrates a high degree of selectivity using a MoS2-decorated graphene-gated AlGaN/GaN high electron mobility transistor (HEMT) with an AlN spacer layer. Design/methodology/approach The sensor was fabricated using a MoS2-graphene gate structure on Si-wafers through standard microfabricaiton techniques. An examination of the dependency of MoS2 thickness was systemically evaluated. As prepared materials were also characterized with X-ray diffraction and Raman spectroscopy. H2 sensing experiments were carried out over a temperature range of 25–250°C under various ppm levels. The optimized devices was further examined under mixed environment of gases. Electrical characteristics were also evaluated. Findings The HEMT sensor exhibited superior H2 sensing efficiency with 3 nm thickness of MoS2. The sensor exhibited remarkable performance at a temperature of 200°C. In addition, it demonstrates quick response and recovery kinetics. It maintained eight times higher sensitivity toward H2 in the interfering gases such as NO2, CH4, CO2, NH3 and H2S under mixed gas conditions. Stable output characteristics and enhanced breakdown resilience across a wide range of gate biases are characteristics by electrical tests. Originality/value These results exhibited that AlGaN/GaN/AlN HEMTs architecture is appropriate for sensing applications that involve high voltage and high temperatures. Moreover, MoS2/graphene hybrid-gated HEMT as a viable system for achieving higher sensitivity and electrical characteristics in H2 detection in dynamic situations.