Research On Formation And Characterization Of PbTe Nanomaterials

In this paper, The PbTe films deposited onto ITO glass substrate and Cr-doped PbTe films were prepared by radio frequency magnetron sputtering. And we present preparation of Cr-doped nanocrystals by Physical Vapor Deposition. X-ray diffraction (XRD), atomic force microscope (AFM) ,scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR) were used to characterize the films. The crystal structure and lattice parameters of films were determined by using XRD. The surface morphology of the films was measured by AFM and SEM. The absorption coefficients and optical band gaps of films were found from FTIR. The sheet resistance of the samples was measured with a Four-point Probe and the resistivity of the film was calculated. All the results are as follows:1. The PbTe films were deposited onto ITO glass substrate by radio frequency magnetron sputtering. Effect of external direct current electrical field applied between substrate and target on the quality of films were investigated. It shows that the suitable bias voltage can improve the quality of the films by attracting the ions to bombard the surface to provide extra energy for the growing films. The property of crystal structure, surface morphology, absorption coefficients, resistivity were improved with the increasing of the bias voltage. It indicates that the bias voltage of -30 V is the best condition for the preparation of PbTe films.2. The Cr-doped PbTe films were deposited onto Si substrate by radio frequency magnetron sputtering and annealing. Effect of annealing time on the quality of films were investigated. It shows that the annealing time have a great influence on the synthesis of Cr-doped PbTe films. It indicates that when the annealing time is15 min, the highly textured film with applanate circle surface morphology could be obtained.3.The Cr-doped PbTe nanocrystals were prepared by Physical Vapor Deposition . Cr thin film was deposited on the Si (1 1 1) substrates by direct current magnetron sputtering. And then the substrates were deposited by heating the PbTe powder. Effect of deposition time were investigated. It shows that deposition time have a great influence on the synthesis of Cr-doped PbTe nanocrystals. It indicates that when the deposition time is 5 min, the better nanocrystals could be obtained.