B.Y. Geng

Raman scattering study of rutile SnO2 nanobelts synthesized by thermal evaporation of Sn powders

The Raman spectrum of single-crystalline rutile tin dioxide (SnO2) nanobelts synthesized by thermal evaporation of tin powders was studied. Three Raman shifts (474, 632, 774 cm−1) showed the typical feature of the rutile phase of the as-synthesized SnO2 nanobelts. It was found that two infrared (IR)-active modes (313 and 690 cm−1) appeared in Raman spectrum and some peaks were broadened.

Synthesis and optical properties of S-doped ZnO nanowires

S-doped ZnO nanowires with an average diameter of 80 nm and length up to several tens of micrometers were produced through a simple physical evaporation approach. The nanowires had a single-crystal hexagonal structure and grew along the [102] direction. Photoluminescence (PL) measurements showed that the doping of sulfur shifted the PL spectrum peak towards short wavelengths, and the doping quantity was found responsible for the different characteristics.

Synthesis and photoluminescence properties of ZnMnS nanobelts

Mn-doped ZnS nanobelts have been prepared through a thermal evaporation method starting with a mixture of acetylacetonates and H2S at 900u200a°C. The nanobelts had a uniform single-crystal hexagonal wurtzite structure and grew along [001] direction. Undoped ZnS nanobelts and ZnMnS nanobelts with 1%, 3%, and 5% Mn so obtained have been characterized by x-ray diffraction, energy dispersive x-ray analysis, and photoluminescence (PL) spectra. PL measurements showed that the fluorescence efficiencies increased and the glow peaks shifted to longer wavelengths as the Mn-doped ratios increased, and the doping was found responsible for the changes in the defect-related emission of the ZnS nanobelts.

Micro-Raman and infrared properties of SnO2 nanobelts synthesized from Sn and SiO2 powders

Rutile structured SnO2 nanobelts have been synthesized from the mixture of Sn powders and SiO2 nanoparticle powders. Each nanobelt has a uniform width of about several hundred nanometers and a thickness of about tens of nanometers along its entire length. Micro-Raman spectrum measurement on the SnO2 nanobelts shows that the first-order Raman A1g mode (632.9u200acm−1) is very strong, and two weak Raman bands 498 and 694u200acm−1 seem to correspond to infrared (IR)-active longitudinal optical (LO) and transverse optical (TO) of A2u modes. In addition, the IR spectrum of the SnO2 nanobelts shows the A2u (LO) (701.9u200acm−1) and Euu200a(1) (TO) (634.5u200acm−1) modes and one surface mode (565.2u200acm−1). The IR-active bands in the Raman spectrum and the surface mode in IR spectrum, which may be due to the nanoscale morphology of the nanobelts.

Large-scale synthesis of single-crystalline Te nanobelts by a low-temperature chemical vapour deposition route

A low-temperature chemical vapour deposition method has been successfully developed for synthesizing single-crystalline Te nanobelts in bulk quantity from Al2Te3 powder and H2O. The nanobelts had a uniform single-crystal hexagonal structure with width ranging from 50 to 300 nm, thickness about 10–20 nm, and lengths up to several tens of micrometres. The growth of Te nanobelts is controlled by a vapour–solid crystal growth mechanism. The method is very simple and the as-synthesized products are pure, so it represents a practical approach to large-scale synthesis of pure single-crystal Te nanobelts.

CdSe-Filled silica nanotubes

The novel nanostructures, CdSe-filled silica nanotubes with diameter about 100 nm and length up to several micrometres, were synthesized through a simple thermochemistry method. CdSe nanorods inside the nanotubes are structurally uniform and single crystalline growing along the < 100 > direction.