Mastura Shafinaz Zainal Abidin
Universiti Teknologi Malaysia

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Humidity effect on electrical properties of graphene oxide back-to-back Schottky diode Shaharin Fadzli Abd Rahman; Nurul Anati Salleh; Mastura Shafinaz Zainal Abidin; Amirjan Nawabjan
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i5.12800

Abstract

A Schottky diode-based sensor is a promising structure for high sensitive and low power sensor. This paper investigates a device called back-to-back Schottky diode (BBSD) for humidity sensing operation. The BBSD provides simpler device configuration that can be fabricated using less complicated process. The current-voltage characteristic of the fabricated BBSD was measured at different relative humidity. From the obtained characteristics, series resistance, barrier height and ideality factor was analyzed. The device current increased at higher humidity level. The current increase could be associated to the decrease in series resistance, barrier height and ideality factor. When humidity decreased from 11 % to 97%, the barrier height showed reduction of 0.1 eV. The barrier height reduction was explained by considering electric field-induced reduction of graphene oxide. The observed result confirmed the device feasibility as promising simple and low cost humidity sensor.
Zinc oxide-paper based sensor for photoconductive ultraviolet detection Mohammad Shafiq Che Soh; Mastura Shafinaz Zainal Abidin; Shaharin Fadzli Abd Rahman; Shuthish Elangkovan; Ahmad Bukhairi Md Rashid
Indonesian Journal of Electrical Engineering and Computer Science Vol 20, No 1: October 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v20.i1.pp60-66

Abstract

Paper based sensor is the new technology to fabricate a simple, portable, and low cost device that exhibits the comparable properties and functions with those fabricated using complex fabrication process. Paper based sensor is usually applied in environmental monitoring, health diagnostics, and food quality control.  This research is focusing on the paper based sensor that will contribute to the development of ultraviolet (UV) sensor. The fabrication of the sensor was done by using different grade of pencil, namely 6B and 2B on different type of paper. The different grade of pencil corresponds to different percentage of graphite and clay. As for the type of paper, A4 printing paper and Whatman filter paper were used. UV sensing operation was analyzed from the measurement of current-voltage (I-V) characteristics under the exposure of UV light. zinc oxide (ZnO) was coated on the sensor to facilitate the detection in the presence of UV. The sample fabricated using 6B pencil grade on A4 printing paper and with ZnO coating showed a better UV sensing performance compared to other samples. This is due to the high conduction of 6B pencil grade and smooth surface of A4 printing paper. The ZnO coating increased the sensor sensitivity and response towards the UV light. These findings provide valuable information which can be used in fabricating a low-cost and simple UV paper sensor.
Synthesis of Germanium Dioxide Microclusters on Silicon Substrate in Non-aqueous Solution by Electrochemical Deposition Mastura Shafinaz Zainal Abidin; Shahjahan Shahjahan; Abdul Manaf Hashim
Indonesian Journal of Electrical Engineering and Computer Science Vol 6, No 1: April 2017
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v6.i1.pp193-199

Abstract

We report the formation of crystalline germanium dioxide (GeO2) microclusters on n-Si (100) electrodeposited in non-aqueous electrolyte (a mixture of 5 vol.% germanium tetrachloride (GeCl4) and dipropylene glycol (C6H14O3) ) at current density of 20 mA/cm2 for 200 sec. Pt, C and Ge are used as an anode while Si acts as a cathode. Field- emission scanning electron microscopy (FESEM) images show that the deposited GeO2 microclusters are having rounded-mushroom-shaped particles with the smallest size of 660 nm. Energy dispersive x-ray (EDX) spectra reveal that the particles are only composed of Ge and O elements. Raman spectra confirm the formation of crystalline GeO2 with trigonal bonding structures in all samples. The photoluminescence (PL) spectra show two significant emission peaks in visible range at 2.27 eV and 2.96 eV, which seems to be attributed by GeO2 and Si defects. C6H14O3 seems to contribute to the formation of GeO2 due to its hygroscopic nature. Such microcluster structures shall provide some potential applications for electronic and optical devices on Si platform.
Characterization of drop-casted graphene/cellulose thin film on printing paper substrate Amirul Hadi Azmi; Shaharin Fadzli Abd Rahman; Mastura Shafinaz Zainal Abidin
Indonesian Journal of Electrical Engineering and Computer Science Vol 19, No 2: August 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v19.i2.pp680-685

Abstract

Paper electronics is an emerging technology to implement flexible and wearable electronics devices via ink printing process. This paper evaluates the feasibility of using conventional printing paper for coating process with graphene/cellulose ink. 4 different types of regularly used conventional printing papers were used as substrates in this work. The conductive graphene ink was prepared through exfoliation of graphite in cellulose solution. The paper substrates surface morphology and sheet resistance of the drop-casted conductive ink on each paper were analyzed and discussed. Glossy paper was found to be suitable paper substrate for the printing of the formulated ink due to its low surface roughness of 16 nm. The value of sheet resistance of the graphene/cellulose thin film can be lowered to 4.11 kΩ/sq by applying multiple drops. This work suggests that conventional printing paper may offer solution for highly scalable and low-cost paper electronics.
Economical fabrication of graphite/paper-based humidity sensor Shuthish Elangkovan; Mastura Shafinaz Zainal Abidin; Shaharin Fadzli Abd Rahman; Mohammad Shafiq Che Soh; Ahmad Bukhairi Md Rashid
Indonesian Journal of Electrical Engineering and Computer Science Vol 20, No 1: October 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v20.i1.pp54-59

Abstract

Paper is regarded as a promising alternative for low-cost and biodegradable substrate. Paper can be a very good humidity detecting substrate due to its capability to absorb water vapour, thanks to its porous surface. This work explores the feasibility of developing a paper-based humidity sensor using simple and low cost fabrication process. Two type of electrode structures, namely interdigitated and parallel electrode, were formed by using two different pencil grade. The pencil grades used were 2B and 6B. The current-voltage (I-V) characteristics of the fabricated device were measured under different relative humidity and its humidity sensing operation was analyzed. It was observed that the sensor with the 6B and parallel electrode configuration was the most responsive to humidity changes while the 6B interdigitated sensor was the second best. The sensors fabricated with the 6B electrodes are better at sensing humidity changes compared to the sensors fabricated using 2B electrodes.