AlGaN/GaN HEMT Based pH Sensor

The sensitivity of GaN HEMTs upon exposure of the gate area to phosphate buffer solution (PBS) has been explored. Output drain characteristic of the device reveals that the drain current decreases linearly with pH values. Higher pH contains less H+ concentration and which is tends to lower the drain current. A high sensitivity of 4.32 µA/mm-pH at Vds = +1 V is obtained.