Surface passivation function of indium-tin-oxide-based nanorod structural sensors

Annealing Effect of Sol-Gel TiO2 Thin Film on pH-EGFET Sensor

“…Extended-gate field-effect transistor (EGFET) device comprises an ion-selective membrane and a metal-oxidesemiconductor field-effect-transistor (MOSFET) which is more corrosion-resistant in saline water and compared to traditional MOSFET sensors, less temperature-sensitive [1][2][3]. In order to achieve a faster response with robust film structure which is more reluctant in acidic, alkaline and organic solvent, the choice of gate materials is very critical [4].…”

Extended-Gate FET Biosensor Based on GaN Micropillar Array and Polycrystalline Layer: Application to Hg2+ Detection in Human Urine

“…For EGFET biosensor, extended-gate electrode materials with large surface area and low impedance are beneficial to improve the sensing performance, e.g., detection sensitivity and limit of detection (LOD). − , To our best knowledge, materials of Si, SnO 2 , ITO, ZnO, and Ga 2 O 3 with nanorod structure has been used as extended-gate to enhance the sensing performance. ,,,− However, these materials have poor electrical conductivity and require to combine with conductive materials (e.g., Al layer, FTO, Ag wire layer, or corresponding seed layer), this would complicate the preparation, reduce repeatability and lead to reduced practicality. ,,,− In contrast, GaN material can achieve not only high surface area by growing nanowire or nanowire array structures but also high electrical conductivity by using low temperature MOCVD growth. − Furthermore, GaN exhibits excellent chemical stability for biosensor application, and the maturity of GaN based electronic devices (e.g., transistor, LED, solar cell) ensure the integration of GaN-based biosensor with GaN electronic devices, which would bring out multifunctional chip. , For EGFET biosensor, compared with the crawling nanowire, vertically grown nanowires (e.g., micropillar array, nanorod array) are independent of each other and can expose more side surfaces, making the nanowire array more sensitive to external charge. , Currently, GaN micropillar array (GMPA) are mainly applied as fluorescence/electrochemical biosensors, only two reports employed crawling GaN nanowires as extended-gate of EGFET biosensor. , But in fact, the detection sensitivity is poor even with high surface area, because the impedance of GaN nanowires grown by conventional processes is large. Thus, preparing GMPA with high electrical conductivity can further improve the detection sensitivity and LOD, but this is still a challenge.…”