Browsing by Author "Hamzah, Azrul Azlan"

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A rapid responding ultraviolet sensor based on multi-parallel aligned ZnO nanowires field effect transistor
(2017-06-15)
Tiong, Teck-Yaw
;
Dee, Chang-Fu
;
Hamzah, Azrul Azlan
;
Goh, Boon Tong
;
Wong, Yuan-Yee
One-dimensional zinc oxide nanowires (ZnO NWs) have been reported to be suitable for UV sensing, but their applications are limited due to restricted surface area which restrains the performance especially in term of response and recovery. In this paper, we fabricate a UV sensor using multi-parallel aligned ZnO NWs based FET in order to overcome the mentioned drawbacks. The sensing characteristics of multi parallel aligned ZnO NWs based FET toward 0.44 mW/cm(2) UV illumination has been examined under depletion and enhancement modes, at ambient conditions. The fabricated UV sensor was found to possess the ability to differentiate UV with different intensity, improved sensitivity (in depletion mode), short response and recovery time (< 1 s), and with high stability. Our paper reports a simple and effective approach for UV sensor fabrication with high responsivity, sensitivity and reproducibility. (C) 2017 Elsevier B.V. All rights reserved.
Normally-Off Tri-Gate GaN MIS-HEMTs with 0.76 m Omega center dot cm(2) Specific On-Resistance for Power Device Applications
(2019-08-01)
Wu, Chia-Hsun
;
Chen, Jian-You
;
Han, Ping-Cheng
;
Lee, Ming-Wen
;
Yang, Kun-Sheng
A GaN metal-insulator-semiconductor high electronmobility transistor (MIS-HEMT) using tri-gate architecture and hybrid ferroelectric charge trap gate stack is demonstrated for normally-off operation. Compared with the conventional planar device, the tri-gate device has the 2-D electron gas (2-DEG) channel exposed on the nanowire sidewalls, so that the trapped charges in the HfON charge-trapping layer can easily deplete the channel from the sidewalls, leading to a high positive threshold voltage (V-th) to realize the normally-off operation. Moreover, through this electrostatic control on the sidewall, a high density of negative charge caused by hybrid ferroelectric charge trap gate stack with the optimized tri-gate structure, the tri-gate device can achieve normally-off GaN device with both low on-resistance (R-ON) and high positive V-th. The designed tri-gate device exhibits a high V-th of +2.61 V at current density (I-DS) = 1 mu A/mm, a high maximum current density (I-DS, MAX) of 896 mA/mm, a low R-ON of 5.0 Omega center dot mm and a high breakdown voltage (BV) of 788 V. To the best of our knowledge, the proposed tri-gate device shows the lowest specific on-resistance (R-ON,R- SP) among reported normallyoff GaN device results with BV > 650 V.
Titanium dioxide-mediated resistive nanobiosensor for E. coli O157:H7
(2020-03-17)
Nadzirah, Sh.
;
Hashim, U.
;
Gopinath, Subash C. B.
;
Parmin, N. A.
;
Hamzah, Azrul Azlan
A titanium dioxide nanoparticle (TiO2 NP)-mediated resistive biosensor is described for the determination of DNA fragments of Escherichia coli O157:H7 (E. coli O157:H7). The sol-gel method was used to synthesize the TiO2 NP, and microlithography was applied to fabricate the interdigitated sensor electrodes. Conventional E. coli DNA detections are facing difficulties in long-preparation-and-detection-time (more than 3 days). Hence, electronic biosensor was introduced by measuring the current-voltage (I-V) DNA probe without amplification of DNA fragments. The detection scheme is based on the interaction between the electron flow on the sensor and the introduction of negative charges from DNA probe and target DNA. The biosensor has a sensitivity of 1.67 x 10(13) omega/M and a wide analytical range. The limit detection is down to 1 x 10(-11) M of DNA. The sensor possesses outstanding repeatability and reproducibility and is cabable to detect DNA within 15 min in a minute-volume sample (1 mu L).