1. Nanostructured ZnO Energy Generator:
Influence of Dimensional and Mechanical Properties
Kwok Siong Teh, School of Engineering, San Francisco University
Research on energy materials is growing in importance as traditional sources of energy are becoming increasingly difficult and costly to obtain. Among energy materials, zinc oxide (ZnO) nanostructures have been heavily researched because they exhibit dual semiconducting and piezoelectric properties, and are bio-safe. To date, little is known about how ZnO’s conversion efficiency and long-term reliability are influenced by fundamental properties such as dimensional and mechanical properties. In addition, time-consuming, high-vacuum and catalyst-assisted fabrication techniques also inhibit the broad applications of ZnO.
We are researching the use of high-frequency RF power as an alternative, energy- and time-efficient means to synthesize ZnO nanostructures. Unlike conventional thermal synthesis methods, our method localizes heating to a targeted, small thermal mass, thereby reducing synthesis time significantly (~ 2 orders of magnitude). We have successfully demonstrate a rapid and catalyst-free method of synthesizing various forms of ZnO nanostructures on Si(100) using a low-power (as low as 65W) RF-induced inductive heating process at ambient pressure. By carefully controlling the reacting gas partial pressures, substrate temperature and heating/cooling rates, we could produce various ZnO morphologies, including (a) nano sheets, (b) tetrapods, (c) high-aspect ratio nanowires, (d) telescopic nanowires, (e) nanoporous nanorods, (f) solid nanorods, and (g) partially hollow nanorods.
ZnO Nanowires
(Scale Bar = 1µm)
EDX of ZnO Nanowire
XRD of ZnO Nanowire