A Novel Transparent AZO-Gated \hbox \hbox\hbox\hbox\hbox pHEMT and Photosensing Characteristics Thereof

• Published in: IEEE transactions on electron devices Vol. 58; no. 3; pp. 725 - 731
• Main Authors: Lee, Ching-Sung, Chou, Bo-Yi, Hsu, Wei-Chou
• Format: Journal Article
• Language: English
• Published: IEEE 01.03.2011
• Subjects: Al-doped ZnO (AZO); Gold; Logic gates; PHEMTs; photosensing; pseudomorphic high-electron mobility transistor (pHEMT); responsivity; Temperature; Thermal stability; thermal threshold stability; transparent gate; voltage gain; Zinc oxide
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2010.2102610

A novel transparent Al-doped ZnO (AZO)-gated Al 0.2 Ga 0.8 As/In 0.2 Ga 0.8 As pseudomorphic high-electron mobility transistor (pHEMT) has been comprehensively investigated. The proposed AZO-gated pHEMT has demonstrated superior temperature-dependent performance, including two-terminal gate-drain breakdown/turn-on voltages of - 63/3.4 (-56.4/3.4) V, an intrinsic voltage gain A V of 257 (176), and a gate voltage swing of 1.18 (1.13) V at 300 (450) K. An excellent thermal threshold coefficient ∂V th /ΘT of -1.8 mV/K was also obtained. A conventional Au-gated device with the same gate dimensions of 1 × 100 μm 2 was also fabricated in comparison. In addition, high optical transmittance values of 82%-98% for incident energy values of 1.24-3.54 eV are achieved in the AZO film. The present AZO-gated HEMT has demonstrated three-terminal tunable optical responsivity due to a photovoltaic effect. Photosensing characteristics under different radiation wavelengths of white light, red light (632 nm), and near infrared (980 nm) are also studied.