Surface reaction on undoped AlGaN/GaN HEMT based two terminal device in aqueous solution

Gallium Nitrides (GaNs) are considered as the most promising materials for liquid-phase sensor applications due to their chemical stability and high internal piezoelectric polarization [1-4]. In this work, the sensing responses of undoped-AlGaN/GaN two terminal devices upon exposure to various pH levels in aqueous solution (a mixture of HCl and NaOH) as well as their possible sensing mechanism have been investigated. No reference voltage or gate voltage is applied. The changes in drain-source current, I_DS as a function of pH level are evaluated.