Browsing by Author "Ahmad, Ishaq"

Now showing 1 - 4 of 4

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.
Structural and photoluminescence investigation on the hot-wire assisted plasma enhanced chemical vapor deposition growth silicon nanowires
(2012-06-01)
Chong, Su Kong
;
Goh, Boon Tong
;
Wong, Yuen-Yee
;
Nguyen, Hong-Quan
;
Do, Hien
High density of silicon nanowires (SiNWs) were synthesized by a hot-wire assisted plasma enhanced chemical vapor deposition technique. The structural and optical properties of the as-grown SiNWs prepared at different rf power of 40 and 80 W were analyzed in this study. The SiNWs prepared at rf power of 40 W exhibited highly crystalline structure with a high crystal volume fraction. X-C of similar to 82% and are surrounded by a thin layer of SiOx. The NWs show high absorption in the high energy region (E > 1.8 eV) and strong photoluminescence at 1.73 to 2.05 eV (red-orange region) with a weak shoulder at 1.65 to 1.73 eV (near IR region). An increase in rf power to 80 W reduced the X-C to similar to 65% and led to the formation of nanocrystalline Si structures with a crystallite size of < 4 nm within the SiNWs. These NWs are covered by a mixture of uncatalyzed amorphous Si layer. The SiNWs prepared at 80 W exhibited a high optical absorption ability above 99% in the broadband range between 220 and similar to 1500 nm and red emission between 1.65 and 1.95 eV. The interesting light absorption and photoluminescence properties from both SiNWs are discussed in the text. (C) 2012 Elsevier B.V. All rights reserved.
The growth of pine-leaf-like hierarchical SnO2 nanostructures
(2014-01-01)
Dee, Chang Fu
;
Tiong, Teck Yaw
;
Varghese, Binni
;
Sow, Chorng-Haur
;
Wong, Yuan-Yee
Pine-leaf-like SnO2 hierarchical nanostructures (NSs) were grown by a two-step vapour transport deposition process with a combination of vapour-solid and vapour-liquid-solid mechanisms at the primary and secondary processes, respectively. This type of hierarchical structure consisted of SnO2 trunk with homo-branching nanowires (NWs). The branched NWs connected the trunk NWs at included angles of 56 degrees and 90 degrees for two different types of hierarchical NSs. Based on the thermodynamic calculation, the formation of branched NWs at those angles are all energetically favourable.
The growth of pine-leaf-like hierarchical SnO2 nanostructures
(2014-01-01)
Dee, Chang Fu
;
Tiong, Teck Yaw
;
Varghese, Binni
;
Sow, Chorng-Haur
;
Wong, Yuan-Yee
Pine-leaf-like SnO2 hierarchical nanostructures (NSs) were grown by a two-step vapour transport deposition process with a combination of vapour-solid and vapour-liquid-solid mechanisms at the primary and secondary processes, respectively. This type of hierarchical structure consisted of SnO2 trunk with homo-branching nanowires (NWs). The branched NWs connected the trunk NWs at included angles of 56 degrees and 90 degrees for two different types of hierarchical NSs. Based on the thermodynamic calculation, the formation of branched NWs at those angles are all energetically favourable.