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Prepared on a glass substrate using a vacuum evaporation method , Nd , Dy - doped CdTe thin film in a nitrogen atmosphere , respectively , at 300 ° C , 400 ° C , 500 ° C on the film to a heat treatment , and by X-ray diffraction , X ray photoelectron spectroscopy and UV-visible spectrophotometer test of the nature of the film . By the test results , analysis and optimization of the preparation process of the CdTe thin film of rare earth Nd, Dy -doped CdTe characteristics . Experimental results show that : high purity elemental cadmium and tellurium in accordance with the atomic ratio of Cd : Te = 1:0.6 mixed evaporation , pure CdTe thin films can be prepared better . Under nitrogen , after T = 500 ° C , t = 10min heat treatment available exclusively for the polycrystalline thin film of CdTe phase ; while in the lower temperature heat treatment under the conditions prevalent in the case of the Te-rich , thin-film , with the heat treatment temperature increases , the phase composition of Te in the film decreased gradually , so that the crystal structure of the sample gradually approaches pure CdTe phase . The rare earth doped CdTe thin film crystallography , optical properties had a discernible impact . Doping of CdTe compound Nd suppressed , while the situation is more serious the Te-rich film , but doped Nd along the (111) CdTe film having the preferred orientation of the crystal orientation , so that the lattice constants of the unit cell volume of the film has been increases, enhanced transmission and optical bandgap decreases slightly . Doping and Dy and doped Nd on the CdTe films have a similar effect , inhibiting the CdTe compound and crystallization , so that the grain size of the film significantly increases the optical band gap is significantly reduced .
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