Znte

OPTOELECTRONICS AND ADVANCED MATERIALS – RAPID COMMUNICATIONS Vol. 4, No. 12, December 2010, p. 2076 – 2079

Synthesis and photoluminescence properties of washboard belt-like ZnSe nanostructures

M. HUANG

School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 333403, P. R. China


Well aligned washboard belt-like ZnSe nanostructures were prepared byatmospheric pressure thermal evaporation of ZnSe nanoparticles without the use of a catalyst. The phase structures, morphologies, and optical properties of the products were investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The temperatures play an important role in controlling the morphologies ofsamples. A vapor-liquid mechanism was proposed for the formation of ZnSe washboard-like structures. The present synthetic route is expected to be applied to the synthesis of other II-VI groups or other group’s semiconducting materials with controllable morphologies.

(Received October 21, 2010; accepted November 29, 2010)

Keyword: ZnSe, Washboard-like nanostructure, Chemical vapor deposition1. Introduction

Low-dimensional structures of compound semicon-ductors, such as nanowires, nanobelts, and nanosaws, are now of significant research interest because of their po-tential applications in nanoscale electronics and photon-ics [1-3]. As one of the most important group II-VI semiconductors, zinc selenide (ZnSe) with the bulk crystal transition energy of 2.7 eV [4] at 300 Kexhibits a great potential for various optoelectronic devices [5] and applications in spintronics [6], as well as for energy up-conversion and terahertz generation in a two-step optical pumping regime [7]. ZnSe has two structural polymorphs of wurtzite and zinc blende [8]. ZnSe-based nanostructures with different forms have been widely investigated recently, such as nanowires, nanobelts, nanoneedles aswell as ZnSe nanorods on in situ synthe-sized ZnSe grains [9].

Several techniques have been developed to control the size and shape of ZnSe nanomaterial such as va-por-phase deposition (CVD), metal-organic chemi-cal-vapor deposition (MOCVD), molecular-beam epitaxy (MBE), and thermo-chemical processes at various growth temperatures has been reported [10]. Basu et al. [11] reported the synthesisof ZnSe nanowires by a mo-lecular-beam epitaxial (MBE) method. Jiang et al. [12] reported the synthesis of ZnSe nanoribbon and nanowires using laser ablation of ZnSe pressed powders. Zhong et al. [13] reported the synthesis of ZnSe colloidal microspheres via a hot injection route by using trioc-tylamine as solvent and with a relatively higher concen-tration of the monomer precursors.
Herein, wereport a simple catalyst-free thermal evaporation technique to synthesize self-assembled ZnSe




nanostructures on graphite substrate. The morphology, crystal structure and the PL spectrum of the ZnSe nanos-tructures are studied.

2. Experimental section

2.1. Preparation of the samples

Source materials of high pure ZnSe (99.99%) and C powders (99.99% micro-powder) with a molarratio of 10:1 in an alumina boat were placed in the heating center of a horizontal alumina tube furnace. After three pieces of graphite wafers were cleaned in piranha solution (30%H2O2/20%H2SO4) and rinsed with de-ionized water, they were placed downstream to act as deposition sub-strates for materials growth. The distance between the graphite substrate and the source material is 15 cm. Prior toheating, the system was evacuated and flushed with high pure Ar for 1 h to eliminate oxygen. Then the furnace was heated to 1000 C, 1100 C and 1200 C, respectively, held at those temperature for1 h, and subsequently cooled to room temperature under a constant flow rate of 50 SCCM Ar.

2.2. Characterization

A Philips XL 30 FEG scanning electron microscope (SEM) with an energy-dispersive X-ray...