TiO2 Nano Flowers Based EGFET Sensor for pH Sensing

Abstract

In this study, pH sensors were successfully fabricated on a fluorine-doped tin oxide substrate and grown via hydrothermal methods for 8 h for pH sensing characteristics. The morphology was obtained by high-resolution scanning electron microscopy and showed randomly oriented flower-like nanostructures. The TiO2 nanoflower pH sensors were measured over a pH range of 2–12. Results showed a high sensitivity of the TiO2 nano-flowers pH sensor, 2.7 (μA)1/2/pH, and a linear relationship between IDS and pH (regression of 0.9991). The relationship between voltage reference and pH displayed a sensitivity of a 46 mV/pH and a linear regression of 0.9989. The experimental result indicated that a flower-like TiO2 nanostructure extended gate field effect transistor (EGFET) pH sensor effectively detected the pH value.

Fabrication and Characterization of In0.9Ga0.1O EGFET pH Sensors

“…The deprotonation led to the threshold voltage (V T(EGFET) ) shift toward the higher bias with increasing the pH value. To find the properties of the In 0.9 Ga 0.1 O EGFET pH sensors, the pH voltage sensitivity can be extracted from the transfer characteristic curves (I DS -V REF ) characteristics and expressed as the following equation [18]:…”

“…The EGFET pH sensors have become processes compatible, convenient, and stable regard to light and outside temperature [15,16]. Recently, several materials were developed and used on the EGFET pH sensors as the sensing membranes, such as zinc oxide (ZnO) [17], titanium dioxide (TiO 2 ) [18], ruthenium oxide (RuO x ) [19], and vanadium oxide (V 2 O 5 ) [20], but scientist still develop more materials for the application. More recently, indium gallium oxide (InGaO) was also found to be a robust material as a promising sensing membrane due to its inherent properties, including wide bandgap, and can be deposited at room temperature [21,22].…”

An EGFET Based Common Source Amplifier as a Low-Frequency Instrumentation Amplifier for Sensitivity Measurement on RuO2 Lactic Acid Biosensor

“…Existing researchers tend to use commercially available MOSFETs as EGFET devices and instead focus on the development of the sensing window [22], [35], [36]. Taking advantage of these works, in this study, we propose a novel measurement method that is emphasized simplicity and effectiveness as well.…”

Highly Sensitive and Selective Sol-Gel Spin-Coated Composite TiO2–PANI Thin Films for EGFET-pH Sensor

“…pH sensors based on metal oxides such as titanium dioxide (TiO 2 ) [ 3 , 4 ], tin oxide (SnO 2 ) [ 5 ], zinc oxide (ZnO) [ 6 , 7 ], ruthenium oxide (RuO 2 ) [ 8 ], nickel oxide (NiO) [ 9 ], copper oxide (CuO) [ 10 ], tantalum oxide (Ta 2 O 5 ) [ 11 ], and others have been studied owing to their high sensitivity to hydrogen ions and a high degree of accuracy. Among these, TiO 2 is a promising material owing to its superior chemical stability, nontoxicity, relatively inexpensive costs, and easy fabrication [ 3 , 4 ]. Cheng Chen et al [ 3 ] developed a porous TiO 2 thin film using a chemical etching method with a reaction time ranging from 15 to 240 min.…”