Catalytic growth of CdS nanobelts and nanowires on tungsten substrates Lifeng Dong a , Jun Jiao a, * , Michael Coulter b , Logan Love a a Department of Physics, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA b Oregon Episcopal School, Portland, OR 97223, USA Received 24 March 2003; in final form 29 May 2003 Published online: 9 July 2003 Abstract In this Letter, we report for the first time the observation of CdS nanobelts. Using a simple thermal evaporation method, CdS nanobelts and nanowires with controllable growth positions were synthesized on tungsten substrates. To explore growth mechanisms of these nanostructures, we have examined the influence of temperature, substrate, and catalyst on their growth properties including morphology, composition, and internal structure. Compared with CdS nanowires, CdS nanobelts were formed in a higher temperature region. However, both growths were initiated by Au catalysts. When silicon or porous silicon was used as substrates, SiO 2 and SiO 2 /CdS composite nanobelts and nanowires were synthesized. The growth mechanisms of these nanostructures are discussed. Ó 2003 Elsevier B.V. All rights reserved. 1. Introduction One-dimensional nanostructures such as na- notubes, nanowires, and nanobelts have attracted much attention due to their novel physical prop- erties and potential applications in nanoscale electronic and optoelectronic devices [1–5]. CdS, one of the most important II–VI group semicon- ductors, is a vital optoelectronic material for laser light-emitting diodes and optical devices based on its nonlinear properties [6]. For one-dimensional CdS nanostructures, CdS nanowires have been synthesized using various methods [7–9], and electrically driven laser properties have been demonstrated on a single CdS nanowire [10]. Compared with the cylindrical nanowires, nano- belts have a high aspect ratio of both width and length to thickness, and so are considered a dis- tinctive subgroup of one-dimensional nanostruc- tured materials. To our knowledge, CdS nanobelts have not been reported to date. To understand the novel optoelectronic and electron field emission properties of CdS due to nanoscale size and di- mensional effects, it is important to be able to synthesize CdS nanobelts with controlled dimen- sions and positions. In this Letter, a simple and efficient method is reported for the patterned growth of CdS nanobelts and nanowires on W Chemical Physics Letters 376 (2003) 653–658 www.elsevier.com/locate/cplett * Corresponding author. Fax: +1-503-725-9525. E-mail address: jiaoj@pdx.edu (J. Jiao). 0009-2614/$ - see front matter Ó 2003 Elsevier B.V. All rights reserved. doi:10.1016/S0009-2614(03)01059-5