GaN thin film based light addressable potentiometric sensor for pH sensing application

Gallium nitride (GaN) is a material with remarkable properties, including wide band gap, direct light emission and excellent chemical stability. In this study, a GaN-based light addressable potentiometric sensor (LAPS) with Si ₃N₄ ~50nm as a sensing membrane is fabricated. By modulated optical excitation from an ultraviolet 365nm light-emitting diode, the photoresponse characteristic and related pH sensitivity of the fabricated GaNbased LAPS is investigated. A Nernstian-like pH response with pH sensitivity of 52.29 mV/pH and linearity of 99.13% is obtained. These results of the GaN-based LAPS show great promise and it could be used as a single chemical sensor or integrated optoelectronic chemical sensor array for biomedical research with high spatial resolution.