Gridless AlGaN/GaN field effect transistor sensor, and preparation method thereof

The invention provides a gridless AlGaN/GaN field effect transistor sensor. According to the gridless AlGaN/GaN field effect transistor sensor, electrodes are arranged on an AlGaN/GaN heterojunction substrate via vapor deposition; the gridless AlGaN/GaN field effect transistor sensor also comprises a passivation layer; a whole source end electrode, a source end electrode PAD, a leakage end electrode, and a leakage end electrode PAD are covered by the passivation layer; the passivation layer used for covering the source end electrode PAD and the leakage end electrode PAD is provided with windows via etching until the PADs are exposed; the gridless AlGaN/GaN field effect transistor sensor also comprises an ion imprinted polymer layer, the ion imprinted polymer layer is arranged on an AlGaN layer, and possesses imprinting holes. The invention also discloses a preparation method of the gridless AlGaN/GaN field effect transistor sensor. The conductive polymer nano composite material possesses single ion identification performance, is capable of improving selective adsorption and anti-interference performance of devices, is capable of realizing quick response and high accuracy quantitative determination, can be reused conveniently and quickly after washing with NaCl solution, is convenient to use, is low in cost, and can be used for water quality on-line monitoring.