All-solid-state AlGaN/GaN-based ion-sensitive heterostructure field effect transistor pH sensor microprobe encapsulated in medical needle

It is very important to monitor pH values. In this paper, we fabricated an all-solid-state AlGaN/GaN-based ion-sensitive heterostructure field effect transistor (ISHFET) sensor microprobe. The microprobe could facilitate measurement of was by packaging the chip into a 21 G medical needle. performance integrated evaluated in range 4–9.18. A sensitivity 143.57 µA/pH can be achieved using with width length ratio 4.2 at drain–source voltage 0.5 V. keeps similar current when values solutions are same. response time 1 s no neutralization reaction occurs. accurately measure under 0.1M interfering ions. This probe-type ISHFET may used medicine or biology, especially detection biological fluid, blood, and some precious samples.