Normally off AlGaN/GaN ion-sensitive field effect transistors realized by photoelectrochemical method for pH sensor application. (April 2019)

• Record Type: Journal Article
• Authors: Li, Liuan; Li, Xiaobo; Pu, Taofei; Liu, Yang; Ao, Jin-Ping
• Is Part Of: Superlattices and microstructures. Volume 128(2019)
• Page Start: 99
• Page End: 104
• Publication Date: 2019-04
• Subjects: AlGaN/GaN ISFET -- pH sensor -- Photo-assisted electrochemical -- Al2O3; Superlattices as materials -- Periodicals; Microstructure -- Periodicals; Semiconductors -- Periodicals; Superréseaux -- Périodiques; Microstructure (Physique) -- Périodiques; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.spmi.2019.01.018
• Languages: English
• ISSNs: 0749-6036

Abstract

Abstract: We fabricate an AlGaN/GaN ion-sensitive field-effect transistor through the photoelectrochemical method for pH sensor application. The photoelectrochemical reaction transforms the AlGaN barrier into oxide, which can deplete the two demensional electron gas to achieve the normally-off operation. Besides, the oxide on the surface enhances the sensitivity to approximately 56.3 mV/pH, a value close to the room temperature Nernstian limit. Based on surface characterization results, the needle-like native oxide (a mixture of Al2 O3 and Ga2 O3 ) is transformed into a smooth Al2 O3 -dominated film. The enhanced surface status and transconductance of the normally-off device is regarded as the possible reason to effective improve the pH sensitivity. Highlights: AlGaN/GaN ISFET pH sensor was fabricated by photoelectrochemical method. The transformation of AlGaN into oxide can realize the normally-off operation and enhance the sensitivity. The enhanced surface status and transconductance is regarded as the possible reason to improve the pH sensitivity.