Junhong Duan

Direct synthesis and characterization of CdS nanobelts

A method to directly synthesize single crystalline CdS nanobelts has been developed. The advantages of the method in rapid synthesis within several minutes and catalyst free comparing to the previous method propose a potential avenue to the further practical device production and applications. The as-synthesized CdS nanobelts grow along the [100] crystalline direction with usually 500–2000nm in width and about tens to several hundred micrometers in length. Two luminescence peaks around 516 and 758nm in room-temperature photoluminescence spectrum are ascribed to the band-to-band and trap emission, respectively.

Multiform structures of SnO2 nanobelts

Multiform SnO2 microstructures were synthesized by a facile thermal evaporation of tin grains. The product was characterized with a variety of techniques to obtain the structural and optical information. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images showed a large percentage of acute angle zigzag nanobelts with perfectly periodic morphology. High resolution transmission electron microscopy (HRTEM) images and selected area electron diffraction (SAED) patterns revealed that the zigzag nanobelts were single crystalline and their zone axis was along the [010] crystal direction. The growth mechanism of zigzag nanobelts was proposed based on TEM characterization and thermodynamic analysis. The zigzag nanobelts were deduced to be formed by changing the growth direction from to [101] or vice versa. The photoluminescence (PL) spectroscopy of the nanobelts showed a broad and strong luminescence emission centred at 550?nm.

Layered tin dioxide microrods

Single-crystalline layered SnO2 microrods were synthesized by a simple tin?water reaction at 900??C. The structural and optical properties of the sample were characterized by x-ray powder diffraction, energy-dispersive x-ray spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, Raman scattering and photoluminescence (PL) spectroscopy. High resolution transmission electron microscopy studies and selected area electron diffraction patterns revealed that the layered SnO2 microrods are single crystalline and their growth direction is along [1 1 0]. The growth mechanism of the microrods was proposed based on SEM, TEM characterization and thermodynamic analysis. It is deduced that the layered microrods grow by the stacking of SnO2 sheets with a (1?1?0) surface in a vapour?liquid?solid process. Three emission peaks at 523, 569 and 626?nm were detected in room-temperature PL measurements.