scholarly journals Spin Speed and Duration Dependence of TiO2Thin Films pH Sensing Behavior

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Muhammad AlHadi Zulkefle ◽  
Rohanieza Abdul Rahman ◽  
Khairul Aimi Yusof ◽  
Wan Fazlida Hanim Abdullah ◽  
Mohamad Rusop ◽  
...  
Keyword(s):  
Thin Films ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Ph Sensor ◽  
Oxide Semiconductor ◽  
Ph Sensing ◽  
Spin Speed ◽  
Coating Method ◽  
Effect Transistor ◽  
Sensing Membrane

Titanium dioxide (TiO2) thin films were applied as the sensing membrane of an extended-gate field-effect transistor (EGFET) pH sensor. TiO2thin films were deposited by spin coating method and the influences of the spin speed and spin duration on the pH sensing behavior of TiO2thin films were investigated. The spin coated TiO2thin films were connected to commercial metal-oxide-semiconductor field-effect transistor (MOSFET) to form the extended gates and the MOSFET was integrated in a readout interfacing circuit to complete the EGFET pH sensor system. For the spin speed parameter investigation, the highest sensitivity was obtained for the sample spun at 3000 rpm at a fixed spinning time of 60 s, which was 60.3 mV/pH. The sensitivity was further improved to achieve 68 mV/pH with good linearity of 0.9943 when the spin time was 75 s at the speed of 3000 rpm.

METAL OXIDE THIN FILMS AS PH SENSING MEMBRANE FOR EXTENDED GATE FIELD EFFECT TRANSISTOR

2016 ◽  
Vol 78 (5-8) ◽  
Author(s):  
Muhammad AlHadi Zulkefle ◽  
Rohanieza Abdul Rahman ◽  
Khairul Aimi Yusof ◽  
Wan Fazlida Hanim Abdullah ◽  
Mohamad Rusop Mahmood ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Sol Gel ◽  
Ph Sensing ◽  
Tio2 Thin Films ◽  
Suitable Material ◽  
Effect Transistor ◽  
Sensing Membrane

In this research, metal oxides (ZnO and TiO2) thin films were fabricated by the sol-gel spin coating method. The thin films were applied as the pH sensing membrane for the extended-gate field effect transistor (EGFET) sensor to distinguish the sensing capability between them. The surface morphology, thin film components and crystalline quality were characterized and the sensor performance of both materials were characterized and compared. The results showed that TiO2 thin film gave higher sensitivity with better linearity compared to the ZnO thin films hence was considered a more suitable material to be used as sensing membrane in EGFET pH sensor compared to zinc oxide. 

scholarly journals Graphene Channel Liquid Container Field Effect Transistor as pH Sensor

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xin Li ◽  
Junjie Shi ◽  
Junchao Pang ◽  
Weihua Liu ◽  
Hongzhong Liu ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Ph Value ◽  
Ph Sensor ◽  
Drain Current ◽  
Fast Response ◽  
Monolayer Graphene ◽  
Ph Sensing ◽  
Order Of Magnitude ◽  
Effect Transistor

Graphene channel liquid container field effect transistor pH sensor with interdigital microtrench for liquid ion testing is presented. Growth morphology and pH sensing property of continuous few-layer graphene (FLG) and quasi-continuous monolayer graphene (MG) channels are compared. The experiment results show that the source-to-drain current of the graphene channel FET has a significant and fast response after adsorption of the measured molecule and ion at the room temperature; at the same time, the FLG response time is less than 4 s. The resolution of MG (0.01) on pH value is one order of magnitude higher than that of FLG (0.1). The reason is that with fewer defects, the MG is more likely to adsorb measured molecule and ion, and the molecules and ions can make the transport property change. The output sensitivities of MG are from 34.5% to 57.4% when the pH value is between 7 and 8, while sensitivity of FLG is 4.75% when thepH=7. The sensor fabrication combines traditional silicon technique and flexible electronic technology and provides an easy way to develop graphene-based electrolyte gas sensor or even biological sensors.

scholarly journals EVALUATION ON THE EGFET PH SENSING PERFORMANCE OF SOL-GEL SPIN COATED TITANIUM DIOXIDE THIN FILM

2021 ◽  
Vol 83 (4) ◽  
pp. 119-125
Author(s):  
Muhammad AlHadi Zulkefle ◽  
Sukreen Hana Herman ◽  
Rohanieza Abdul Rahman ◽  
Khairul Aimi Yusof ◽  
Aimi Bazilah Rosli ◽  
...  
Keyword(s):  
Thin Film ◽  
Tio2 Thin Film ◽  
Drift Rate ◽  
Sol Gel ◽  
Ph Sensor ◽  
Ph Sensing ◽  
Coating Method ◽  
Effect Transistor ◽  
Sensing Membrane ◽  
Sensing Performance

For this study, TiO2 thin film was fabricated using the sol-gel spin coating method. The fabricated film was then applied as a sensing membrane in an extended gate field effect transistor (EGFET) pH sensor system. The pH sensing performance of the sol-gel spin-coated TiO2 was evaluated in terms of sensitivity, linearity, and hysteresis where the value obtained was 58.70 mV/pH, 0.9922, and 86.17 mV respectively. The drift rate of the sample when being measured for 12 consecutive hours was also determined where measurement in pH 4, pH 7, and pH 10 yield drift rate of 1.72 mV/h, 4.14 mV/h, and 6.05 mV/h respectively.  Besides that, the TiO2 was characterized for its thickness (24.32 nm) and surface roughness (5.129 nm). From the results obtained, it was found that sol-gel spin-coated TiO2 thin film with thickness between 20 - 29 nm will have high pH sensitivity (more than 50 mV/pH).

scholarly journals Deposition of High-k Samarium Oxide Membrane on Polysilicon for the Extented-Gate Field-Effect Transistor (EGFET) Applications

2014 ◽  
Vol 17 (1) ◽  
pp. 013-016
Author(s):  
Chyuan-Haur Kao ◽  
Hsiang Chen ◽  
Jer-Chyi Wang ◽  
Yu-Cheng Chu ◽  
Chiao-Sung Lai ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
High Sensitivity ◽  
Great Promise ◽  
Ph Sensing ◽  
Samarium Oxide ◽  
High K ◽  
Effect Transistor ◽  
Oxide Membrane ◽  
Sensing Membrane

The paper reports samarium oxide as pH. sensing membrane on polysilicon combined with proper post deposition annealing for the extended-gate field-effect transistor (EGFET) application at the first time. It can be found that the high-k samarium oxide membrane annealed at 700 ºC could obtain high sensitivity, high linearity, low hysteresis voltage, and low drift rate due to improvements ofcrystalline structures. The high-k Sm2O3 sensing membrane shows great promise for future bio-medical device applications.

scholarly journals Electrical Characteristics and pH Response of a Parylene-H Sensing Membrane in a Si-Nanonet Ion-Sensitive Field-Effect Transistor

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3892 ◽  
Author(s):  
Bo Jin ◽  
Ga-Yeon Lee ◽  
ChanOh Park ◽  
Donghoon Kim ◽  
Wonyeong Choi ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Ph Value ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Frequency Noise ◽  
Electrical Characteristics ◽  
Ph Sensing ◽  
Effect Transistor ◽  
Sensing Membrane

We report the electrical characteristics and pH responses of a Si-nanonet ion-sensitive field-effect transistor with ultra-thin parylene-H as a gate sensing membrane. The fabricated device shows excellent DC characteristics: a low subthreshold swing of 85 mV/dec, a high current on/off ratio of ~107 and a low gate leakage current of ~10−10 A. The low interface trap density of 1.04 × 1012 cm−2 and high field-effect mobility of 510 cm2V−1s−1 were obtained. The pH responses of the devices were evaluated in various pH buffer solutions. A high pH sensitivity of 48.1 ± 0.5 mV/pH with a device-to-device variation of ~6.1% was achieved. From the low-frequency noise characterization, the signal-to-noise ratio was extracted as high as ~3400 A/A with the lowest noise equivalent pH value of ~0.002 pH. These excellent intrinsic electrical and pH sensing performances suggest that parylene-H can be promising as a sensing membrane in an ISFET-based biosensor platform.

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