| More and more attention has been attracted on Cd1-xZnxTe crystal recently for its excellent optical and electronical properties. As we know, when x is equal to 0.04, Cd1-xZnxTe is used as epitaxial substrates of Hg1-yCdyTe. When x is in between 0.05 to 0.5, it can be used for fabrication high quality x-ray and y -ray detectors, photo electrical modulators, film solar cells and so on. Particularly, the x-ray and y -ray detectors made from Cd0.9Zn0.1Te will reduce the dark current and improve energy resolution for the use at room temperature. At the same time, this kind of detectors possesses high mechanical strength and prominent thermal stabilization.Several ingots of Cd0.96Zn0.04Te and Cd0.9Zn0.1Te are produced by ACRT-Bridgman method, and their optical and electronical properties are tested. The measurements on IR transmission, composition distribution and resistivity reveal that its properties cannot satisfy the requirements of high quality x-ray and y -ray detectors at the as-grown state. Some further treatments are necessary.Three annealing methods are proposed in order to upgrade the crystal properties. By comparing the IR transmission, composition distribution and impurity concentration of the crystal after each treatment with those of as-grown wafers, the most valuable and reliable one is selected. After the annealing, the impurity concentration is reduced and the composition distribution is homogenized. Meanwhile, the IR transmission is increased to exceeding 60%. What's more, after the treatment the resistivity is raised by 2 to 3 orders, reaching 1010 Ω cm, which satisfies the requirement for fabrication of x-ray and y -ray detectors. |
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