Tzer-Shen Lin

ZnO Nanowire-Based CO Sensors Prepared at Various Temperatures

/Sitemplates at various temperatures. It was found that the average length of the nanowires increased while the average diameter ofthe nanowires decreased as we increased the growth temperature from 600 to 700°C. It was also found that the nanowires becamesignificantly shorter as the growth temperature was increased. By measuring the resistivity change of the samples at 320°C, it wasfound that the sensor responses were of 3, 17, 57, 7.5, and 5% for the ZnO nanowires grown at 600, 650, 700, 750, and 800°C,respectively. Furthermore, it was found that the sensitivity of the sensor was relatively increased when the concentration ofinjected CO gas increased.© 2007 The Electrochemical Society. DOI: 10.1149/1.2789813 All rights reserved.Manuscript submitted June 25, 2007; revised manuscript received August 29, 2007. Available electronically October 9, 2007.

Indium-diffused ZnO nanowires synthesized on ITO-buffered Si substrate

We report the synthesis of well aligned, high density, vertical single-crystal ZnO nanowires on ITO-buffered Si substrate (ITO is indium tin oxide) at 550 ◦ Cf or 30 min. It was found that the average length and diameter of the ZnO nanowires were around 3.5 µ ma nd30 nm, respectively. It was also found that the ZnO nanowires were oriented in the (002) direction with extremely good crystal quality. Furthermore, it was found that In diffusion occurred at the bottom of the ZnO nanowires. (Some figures in this article are in colour only in the electronic version)

Crabwise ZnO Nanowire UV Photodetector Prepared on ZnO : Ga/Glass Template

Vertical well-aligned and crabwise ZnO nanowires were prepared on patterned ZnO:Ga/glass substrates by reactive evaporation method under different growth conditions. The average length and diameter of vertical well-aligned ZnO nanowires were around 1 mum and 50-100 nm, respectively. In contrast, the average length and diameter of crabwise ZnO nanowires were around 5 mum and 30 nm, respectively. Upon illumination with UV light (lambda = 362 nm), it was found that measured responsivities were 0.015 and 0.03 A/W for the crabwise ZnO nanowire photodetector biased at 10 and 15 V, respectively. Furthermore, a rejection ratio of approximately 10 was obtained for the crabwise ZnO nanowire photodetector with an applied bias of 10 V.

Growth and Characterization of Sparsely Dispersed ZnO Nanowires

This investigation describes the growth of sparsely dispersed vertical ZnO nanowires on sputtered-ZnO:Ga/sapphire templates by self-catalyzed vapor liquid solid method. Experimental results indicate that these ZnO nanowires grew with the preferred (002) orientation with good crystal quality. Conductive diamond-coated point probe forms Schottky contact on single ZnO nanowire with a sharp turn-on voltage of -2.5 V and a barrier height of approximately 0.38 eV.

Influence of the Formation of the Second Phase in ZnO ∕ Ga Nanowire Systems

This investigation describes the synthesis and formation of the second phase of high-density arrays of vertically aligned ZnO:Ga nanowires on ZnO/glass substrates at 600°C. As the concentration of the Ga is increased, the nanowire became shorter without any change in its diameter. The formation of the second phase, ZnGa 2 O 4 (JCPDS no. 38-1240), was verified by X-ray diffraction and high-resolution lattice imagery, even though the concentration of the Ga was only 3.5 atom %. The formation of the second compound substantially influenced the physical properties of the nanowire.