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

fYear

2007

fDate

20-22 Dec. 2007

Firstpage

283

Lastpage

286

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/EDSSC.2007.4450117

Filename

4450117