Semiconductor Based Liquid Phase Sensor for Selective Ion Sensing Application


Figure above : Open-gate liquid-phase sensor fabricated on undoped-AIGaN/GaN high-electron-mobility-transistor (HEMT)



Many semiconductor materials have been tested for their suitability as ion sensors; especially there is an emerging interest in the use of wide band gap semiconductors as sensitive chemical sensors. AlGaN/GaN high-electronmobility- transistor (HEMT) structures have been extremely useful for gas and liquid-phase sensors due to their excellent properties. Sensing responses of an open-gate liquid-phase sensor fabricated on undoped-AlGaN/GaN high-electron-mobility-transistor (HEMT) structure have been extremely useful for gas and liquid phase sensors due to their excellent properties. The open-gate undoped AlGaN/GaN HEMT structure is capable of distinguishing pH level in aqueous electrolytes and exhibits linear sensitivity, where the high sensitivity of 1.9 mA/pH or 3.88 mA/mm/pH was obtained. The fabricated open-gate undoped-AlGaN/GaN structure is expected to be suitable for pH sensing application.