Abstract
In this article we demonstrate the high sensitivity AlGaN/GaN circular HEMT (C-HEMT) hydrogen gas sensor with new gate interfacial Pt/NiO layer. The wide band-gap III-nitride semiconductor heterostructure allows the sensor operation at elevated temperatures. Likewise, the C-HEMT sensing device is easy to prepare because the MESA insulation step can be omitted. Moreover, the I-V characteristics of ring gate diodes with a dominant thermionic emission of electrons can be easly achieved by elimination of tunneling currents induced on the MESA-etched edges. The Pt/NiO stacked gate absorption layer has nanocrystalline structure, what increases the surface-to-volume ratio. Consequently, the hydrogen gas is more efficiently dissociated at low temperature. Comparing to reference Pt/AlGaN/GaN diode sensor, the optimum operation temperature decreases from 250 oC towards 50oC and the hydrogen detection efficiency is enhanced about 10 times. This is desirable for battery-powered sensors with low current consumption. On the other hand, the fabricated sensor shows longer reaction and regeneration time constants. This is due to longer diffusion path that hydrogen atoms must overcome to reach the AlGaN semiconductor surface.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
