Viscosity-dependent drain current noise of AlGaN/GaN high electron mobility transistor in polar liquids

J. Y. Fang, G. Y. Lee, J. I. Chyi, C. P. Hsu, Y. W. Kang, K. C. Fang, W. L. Kao, D. J. Yao, C. H. Hsu, Y. F. Huang, C. C. Chen, S. S. Li, J. A. Yeh, F. Ren, Y. L. Wang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The drain current fluctuation of ungated AlGaN/GaN high electron mobility transistors (HEMTs) measured in different fluids at a drain-source voltage of 0.5 V was investigated. The HEMTs with metal on the gate region showed good current stability in deionized water, while a large fluctuation in drain current was observed for HEMTs without gate metal. The fluctuation in drain current for the HEMTs without gate metal was observed and calculated as standard deviation from a real-time measurement in air, deionized water, ethanol, dimethyl sulfoxide, ethylene glycol, 1,2-butanediol, and glycerol. At room temperature, the fluctuation in drain current for the HEMTs without gate metal was found to be relevant to the dipole moment and the viscosity of the liquids. A liquid with a larger viscosity showed a smaller fluctuation in drain current. The viscosity-dependent fluctuation of the drain current was ascribed to the Brownian motions of the liquid molecules, which induced a variation in the surface dipole of the gate region. This study uncovers the causes of the fluctuation in drain current of HEMTs in fluids. The results show that the AlGaN/GaN HEMTs may be used as sensors to measure the viscosity of liquids within a certain range of viscosity.

Original languageEnglish
Article number204503
JournalJournal of Applied Physics
Volume114
Issue number20
DOIs
StatePublished - 28 Nov 2013

Fingerprint

Dive into the research topics of 'Viscosity-dependent drain current noise of AlGaN/GaN high electron mobility transistor in polar liquids'. Together they form a unique fingerprint.

Cite this