المستخلص: |
In this article, we study the effect of increasing cadmium content on optoelectronic properties, as we know that cadmium the same zinc group (group 12), so it has similar properties. The thin films for Si10Ge10Zn80-xCdx system (where x=5&15) were studied in the temperature range from 35 to 400 ˚C. This system of two samples were prepared was deposited on borosilicate glass substrates. The two configurations of multilayers are pure silicon (Si), germanium (Ge), and Zinc (Zn) at high concentration, doped of Cadmium (Cd) (Cd-doped). The influence of annealing on the structure and stability of the samples has been studied by X-ray diffraction. The changes in optoelectronic properties are attributed partially to decreasing the optical band gap Eg and increasing the Urbach energy Eu with increasing ratio of doped of (Cd) (Cd-doped) to the high concentration of Zinc (Zn). The doping has a great effect on the Eg and Eu, found that Cd-doping increase, the energy gap decreasing from 0.94 to 0.76 eV. Another reason for the changes in the energy gap Eg and the Urbach energy Eu is the crystallization, it is occur only in Ge matrix because the crystallizing temperature of the germanium (about 300°C). This effect is not clear with increasing cadmium doping due to the stability of the sample composition. It has been shown their conductivity also increase with annealing and increasing the ratio of Cd-doped zinc concentration.
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