Synthesis, Photoluminescence Characterization Of Zn_xCd_1-xS Nanocrystals And Nanofilms

The ZnxCd1-xS (0≤x≤1) nanocrystals with high crystallinity and uniform size were successfully synthesized by simple hydrothermal method. The SEM, TEM, XRD, room temperature photoluminescence, UV-vis absorption spectra of the synthesized ZnxCd1-xS were studied. The main results achieved from this part of thesis are listed as the followings.1. The TEM photograph and the X-ray diffraction patterns of the synthesized ZnxCd1-xS showed the wurtzite phase formation for each x value. There was no phase transition occurred due to the increase of Zn content from 0 to 1.2. Calculated from the XRD data, the average particle sizes of the synthesized ZnxCd1-xS were about 20 to 30nm for the synthesized ZnxCd1-xS for different x (Zn content). The lattice constant a was decreasing from 4.14 to 3.85 A accompany with the x (Zn content) increasing from 0 to 1.3. The photoluminescence emission peaks of the synthesized ZnxCd1-xS continuously shifted towards the lower wavelength region as the increase of Zn content. But the photoluminescence emission pattern of Zn0.80Cd0.20S has a unique double peak for the overlap of the ZnS and CdS band energy. The evolution behavior of the PL and absorption spectra of ZnxCd1-xS were attributed to the quantum confinement effect and the lattice constant variation with Zn/Cd ratio.Then, the ZnxCd1-xS/Si-NPA were synthesized by dip-coating method. The SEM, XRD, room temperature photoluminescence of the synthesized ZnxCd1-xS/Si-NPA were studied. The main results achieved from this part of thesis are listed as the followings.1. Silica gel is a useful medium as the dip-coating liquid to compound ZnxCd1-xS and Si-NPA. The particular surface morphology of ZnxCd1-xS particular in ZnxCd1-xS/Si-NPA was almost same to which in the ZnxCd1-xS powder samples.2. Calculated from the XRD data, the average particle sizes of the synthesized ZnxCd1-xS/Si-NPA were about 20 to 30nm, which was almost same to the ZnxCd1-xS powder. 3. There are four peaks in the photoluminescence emission pattern of ZnxCd1-xS/Si-NPA. One of the PL peaks shifted towards the lower wavelength region as the Zn content of the synthesized samples increasing.