Method and device for growing cadmium zinc telluride crystals in mobile tellurium solvent melting zone

Abstract

The invention relates to a device and a method for growing cadmium zinc telluride crystals in a mobile tellurium solvent melting zone and belongs to the technical field of the growth of special crystals. The method is characterized by comprising the following steps of: feeding 99.99999 percent high-purity raw materials of which the stoichiometric proportion meets Cd1-xZnxTe (x=0.04-0.8) into two quartz tubes; adding 30 to 80 mass percent of excessive tellurium (Te) into one of the quartz tubes; vacuumizing and sealing the quartz tubes respectively and synthesizing materials in the quartz tubes to obtain polycrystalline rods and alloys rich in the Te in a rocking furnace; feeding seed crystals, the alloys rich in the Te and the polycrystalline rods into a long crystal tube, vacuumizing, sealing and placing the long crystal tube in a furnace body, wherein the alloys rich in the Te are positioned in a high-frequency induction heater at the temperature of 700 to 950 DEG C; raising the heater at a speed of 0.02 to 2mm/h and rotating the long crystal tube at the same time; and adding excessive Te in an alloy area rich in the Te to obviously reduce the melting point to ensure that the polycrystalline rods are continuously dissolved from the upper part of melt and cadmium zinc telluride single crystals are continuously precipitated from the lower part of the melt along with the rising. The method and the device for growing the cadmium zinc telluride crystals have the advantages of obviously reducing the growing temperature and the impurity concentration of the crystals.

Description

technical field [0001] The invention relates to a method and a device for growing a cadmium zinc telluride crystal in a moving tellurium solvent melting zone, and belongs to the technical field of special crystal growth technology. Background technique [0002] Since CdZnTe (CZT) has a higher average atomic number and a larger forbidden band width, the CZT detector has a larger absorption coefficient and a higher count rate, especially at room temperature without any cooling equipment. Work, so it is smaller and more convenient to use. At present, the wide application of CZT detectors is mainly limited by several aspects such as crystal performance, volume and cost. The preparation method of crystals is mainly to grow CZT crystals by high-voltage Bridgman method or improved vertical Bridgman method. [0003] However, in order to obtain high-resistance crystals, these two methods are usually implemented by doping shallow donor impurities to compensate for shallow acceptors i...

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Problems solved by technology

[0003] However, in order to obtain high-resistance crystals, these two methods are usually implemented by doping shallow donor impurities to compensate for shallow acceptors in the crystal, but it is difficult to make the two concentrations nearly equal, and deep energy levels must be introduced. to "pin" the remaining shallow energy levels

But the deep energy levels are traps and recombination centers, such as the introduced deep energy level density is greater than 10 13 / cm3, will greatly reduce the value of μτ (the product of carrier lifetime and mobility)

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