Title :
A GaAs-based Heterostructure Field-Effect Transistor-Type Hydrogen Sensor in Air and N2 Ambiances
Author :
Hung, C.W. ; Chen, H.I. ; Tsai, T.H. ; Chen, L.Y. ; Chu, K.Y. ; Liu, W.C.
Author_Institution :
Nat. Cheng-Kung Univ., Tainan
Abstract :
An interesting hydrogen sensor based on the Pd/GaAs heterostructure field-effect transistor (HFET) is fabricated and investigated under various hydrogen concentrations in air and N2 environments. Experimentally, in nitrogen (air) ambiances, the studied sensor exhibits a hydrogen detection limit of 4.3 ppm H2/N2 (98 ppm H2/air) at 403 K, a high sensitivity of 1295 muA/mm-ppm H2/N2 (275.8 muA/mm-ppm H2/air) in 14 ppm H2/N2 (H2/air) at 303 K, and a large initial rate of 774.4 (589.8) muA/s in 9970 ppm H2/N2 (H2/air) at 363 K. However, the studied sensor shows a longer recovery time in nitrogen than in air due to the lack of additional desorption process. From the experimental results, it is speculated that the oxygen in air occupies the adsorption sites and reduces the adsorbed hydrogen atoms at the Pd/GaAs interface.
Keywords :
III-V semiconductors; adsorption; chemical variables measurement; desorption; gallium arsenide; gas sensors; high electron mobility transistors; GaAs; HFET fabrication; Pd; adsorption sites; desorption process; heterostructure field-effect transistor; hydrogen sensor; temperature 303 K; temperature 363 K; temperature 403 K; Chemical sensors; Gallium arsenide; Gas detectors; Gases; HEMTs; Hydrogen; MODFETs; Nitrogen; Schottky barriers; Sensor phenomena and characterization;
Conference_Titel :
Electron Devices and Solid-State Circuits, 2007. EDSSC 2007. IEEE Conference on
Conference_Location :
Tainan
Print_ISBN :
978-1-4244-0637-1
Electronic_ISBN :
978-1-4244-0637-1
DOI :
10.1109/EDSSC.2007.4450117
