Wei Zhipeng

Influence factors and mechanism of emission of ZnS:Cu nanocrystals

Copper-doped ZnS (ZnS:Cu) nanocrystals are synthesized by the sol?gel method. The average size of the ZnS:Cu nanocrystals is 3.1?nm. The x-ray diffraction indicates that increasing the Cu-dopant concentration results in a large shift in the diffraction angle. The effects of the dopant concentration, the reactant ratio, and aging temperature on the optical properties of the ZnS:Cu nanocrystals are also investigated. The fluorescence emission mechanism is analyzed by peak deconvolution using Gaussian functions. We find that the emission of the ZnS:Cu nanocrystal is composed of different luminescence centers at 430, 470, 490, 526, and 560?nm. The origins of these emissions are discussed and demonstrated by controlled experiments.

Fabrication and Characteristic of ZnO Glucose Oxidase Enzyme Electrode Based on Flexible Substrate

Well-aligned ZnO nanorods(NRs) were grown on the ZnO seed layer of a polyimide(PI) coated flexible substrate using the hydrothermal method and used as a support matrix for the immobilization of glucose oxidase(GOx).The crystal structures and surface morphologies of the so-formed ZnO nanorods were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM).GOx was immobilized on the surfaces of ZnO nanorods using electrostatic adsorption.Both the GOx and modified ZnO nanorods were characterized by UV-visible spectroscopy,and the absorption peaks of ZnO and GOx can be detected.Fourier transform infrared(FTIR) spectroscopy were used to characterize the chemical structure of the glucose oxide,which still maintained its biological activity.This study provides an experiment basis for the preparation of flexible glucose biosensors owing to the flexibility of the enzyme electrode,which showed a sensitive current response when tested by cyclic voltammetry.

The Ohmic contact of n-GaSb with a Mo diffusion barrier

Ohmic contacts to n-type GaSb have been investigated. Some drawbacks are associated with conventional Ni/AuGe/Au Ohmic contact of n-GaSb, so we propose to add a Mo diffusion barrier between AuGeNi and Au layer and carry out the structure fabrication experiment. The results show that the new metallization decreases the specific contact resistance and can be annealed at wide temperature range. It is more important that the introduction of Mo inhibits effectively the in-diffusion of atoms by the analysis of AES. It also makes the new metallization have a better surface morphology, wider temperature range and benefit for the stability of the devices.