scholarly journals Fabrication And pH Sensing Characteristics Measurement of Back Gate ZnO Thin Film Planar FET

Author(s):  
Ankita Porwal ◽  
Chitrakant Sahu

Abstract Here in we demonstrate the design of a low- cost zinc oxide (ZnO) thin-film planar transistor-based pH sensor controlled by the bottom gate fabricated by a fairly simple fabrication approach. The performance of the fabricated device is evaluated by electrical as well as surface characterization. The surface morphology is analyzed by scanning electron microscope (SEM) and atomic force microscopy (AFM) and it shows surface properties that are essential for a device to function as a pH sensor. The fabricated thin-film FET comprises Zinc Oxide (ZnO) as a channel layer of length 6 µm and thickness 200 nm, Silicon Nitride (Si3N4) as a pas- sivation layer, and Aluminum (Al) as a contact layer. The effect on pH sensitivity for varied channel lengths (6 µm, 12 µm, and 15 µm) is also examined and opti- mum results have been achieved at channel length = 6 µm. The change in threshold voltage (ΔVth) & change in current (ΔImax) are used as a sensing metrics to an- alyze the sensing performance of the device. The device shows excellent pH sensitivity in terms of average cur- rent and average voltage sensitivity 120.97 mA/pH and 97.85 mv/pH respectively at pH ranging from 3.2 to 11.1 with best pH stability (linearity) for pH value 4 to 10. The voltage sensitivity is higher than the Nernstian value (59 mv/pH) at room temperature.

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 42
Author(s):  
Shimrith Paul Shylendra ◽  
Wade Lonsdale ◽  
Magdalena Wajrak ◽  
Mohammad Nur-E-Alam ◽  
Kamal Alameh

In this work, a solid-state potentiometric pH sensor is designed by incorporating a thin film of Radio Frequency Magnetron Sputtered (RFMS) Titanium Nitride (TiN) working electrode and a commercial Ag|AgCl|KCl double junction reference electrode. The sensor shows a linear pH slope of −59.1 mV/pH, R2 = 0.9997, a hysteresis as low as 1.2 mV, and drift below 3.9 mV/h. In addition, the redox interference performance of TiN electrodes is compared with that of Iridium Oxide (IrO2) counterparts. Experimental results show −32 mV potential shift (E0 value) in 1 mM ascorbic acid (reducing agent) for TiN electrodes, and this is significantly lower than the −114 mV potential shift of IrO2 electrodes with sub-Nernstian sensitivity. These results are most encouraging and pave the way towards the development of miniaturized, cost-effective, and robust pH sensors for difficult matrices, such as wine and fresh orange juice.


2018 ◽  
Vol 1083 ◽  
pp. 012055 ◽  
Author(s):  
Fayroz A. Sabah ◽  
Naser M. Ahmed ◽  
Z. Hassan

Author(s):  
Akintunde Ayodeji Ajayi ◽  
Aderemi Babatunde Alabi ◽  
Olutayo Wale Abodunrin ◽  
Kazeem Adeleke Musiliyu

Zinc Oxide (ZnO) thin film has been synthesized using the chemical spray pyrolysis technique and ethylene glycol has been used as solvent during the synthesis. X-ray diffraction (XRD) results show cubic and tetragonal phases of ZnO and the grain size was calculated to be 2.57nm. Optical characterization reveals very high transmittance within the visible-ultraviolet region and a bandgap of 3.49 eV was obtained for ZnO thin film. Scanning Electron Microscopic (SEM) analysis showed a void-free non-homogenous surface.


Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 251
Author(s):  
Chih-Chiang Yang ◽  
Kuan-Yu Chen ◽  
Yan-Kuin Su

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.


2012 ◽  
Vol 239-240 ◽  
pp. 1585-1588 ◽  
Author(s):  
Yuh Chung Hu ◽  
David T.W. Lin ◽  
Hai Lin Lee ◽  
Pei Zen Chang

The effect of Zinc-Oxide (ZnO) thin film annealed in different ambiences is presented. To achieve low cost and environmentally friendly process, ZnO aqueous solution is synthesized by dissolving zinc acetate dihydrate in deionized water directly. Zinc oxide aqueous solution of high solubility and stability is presented. High quality and dense Zinc oxide thin film is formed by spin coating. Annealing temperatures are in the range of 300 °C~500 °C, and annealing ambiences of both air and N2 are discussed.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Xin Li ◽  
Junjie Shi ◽  
Junchao Pang ◽  
Weihua Liu ◽  
Hongzhong Liu ◽  
...  

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.


2013 ◽  
Vol 667 ◽  
pp. 549-552
Author(s):  
A.S.M. Rodzi ◽  
Mohamad Hafiz Mamat ◽  
M.N. Berhan ◽  
Mohamad Rusop Mahmood

The properties of zinc oxide thin films were prepared by sol-gel spin-coating method have been presented. This study based on optical and electrical properties of ZnO thin film. The effects of annealing temperatures that exposed with two environments properties have been investigated. Environments exposed in room (27°C) and hot (80°C) temperatures which are stored by various days. Solution preparation, thin film deposition and characterization process were involved in this project. The ZnO films were characterized using UV-Vis-NIR spectrophotometer for optical properties. From that equipment, the percentage of transmittance (%) and absorption coefficient spectra were obtained. With two environments showed have different absorption coefficient are reveal and all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties. From SEM investigations the surface morphology of ZnO thin film shows the particles size become smaller and denser in hot temperatures while in room temperatures have porosity between particles.


RSC Advances ◽  
2016 ◽  
Vol 6 (72) ◽  
pp. 67715-67723 ◽  
Author(s):  
Warda Hadouchi ◽  
Jean Rousset ◽  
Denis Tondelier ◽  
Bernard Geffroy ◽  
Yvan Bonnassieux

A sputtered ZnO thin film was used as electron extraction layer, in a planar perovskite based solar cell. As a result a maximum power conversion efficiency (PCE) of 14.2%, measured at reverse scan, has been demonstrated.


2011 ◽  
Vol 335-336 ◽  
pp. 478-482 ◽  
Author(s):  
Xin Liang Cao

For different gas sensing, the preparation of Zinc Oxide (ZnO) thin film gas sensor has its particularity. In this paper, three kinds of preparation methods, fitting for CO and methane and CO2 sensing, are introduced. Moreover, the sensitivity is respectively analyzed as gas sensors. The reference is provided for the preparation and applications of ZnO thin film gas sensor.


2011 ◽  
Vol 312-315 ◽  
pp. 1126-1131
Author(s):  
Mohamad Hafiz Mamat ◽  
Zuraida Khusaimi ◽  
Mohamad Mahmood Rusop

Zinc oxide (ZnO) nanostructures with different kind of morphologies were synthesized on glass substrates via the hydrothermal aqueous chemical growth method utilizing c-axis oriented ZnO thin film as seeded catalyst. By preparing ZnO thin film at different molar concentrations between 0.2~1.0 M, oval shaped ZnO nanostructures mixed with ZnO nanowires and rod shaped ZnO nanostructures mixed with ZnO nanowires were produced after immersion process into 0.0002 M zinc nitrate solution for 24 hour. The XRD spectra show synthesized ZnO nanostructures were ZnO hexagonal wurtzite crystalline. The photoluminescence (PL) measurement indicates the luminescences of the samples were depending on the shapes of ZnO nanostructure.


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