Preparation method for cadmium telluride

Abstract

The invention discloses a preparation method for cadmium telluride. The preparation method sequentially comprises the following steps: qualified tellurium powder and cadmium powder are taken according to the molar ratio of 1:1 and then subjected to homogeneous mixing, the mixed raw materials subjected to homogenizing are loaded into a graphite boat, and the graphite boat is placed into a synthesis furnace for first synthesis; the material obtained after first synthesis is taken out of the graphite boat and crushed; the crushed material is loaded into the graphite boat, and the graphite boat is placed into the synthesis furnace for second synthesis; screening and ball milling are performed, wherein in the processes of the first synthesis and the second synthesis, multistage temperature rising and temperature dropping are performed under the protection of nitrogen and hydrogen. According to the invention, homogeneous treatment is performed on the tellurium powder and cadmium powder firstly so as to enable the two raw materials to be mixed fully and uniformly, meanwhile, the defect that the cadmium powder is easy to oxidize is overcome, the two raw materials can be synthesized preliminarily under relatively low temperature, purity of a synthesized product is improved, and the utilization ratios of raw materials are increased; synthesis is performed for two times, so that the raw materials react fully, thereby improving the purity and yield of the product finally.

Description

technical field [0001] The invention relates to the technical field of semiconductor materials, in particular to a preparation method of cadmium telluride. Background technique [0002] Cadmium telluride is a semiconductor compound synthesized by cadmium and tellurium. It is brown-black crystal powder, insoluble in water and acid, and can be decomposed by nitric acid. ideal photoelectric conversion material. [0003] At present, there are many ways to synthesize cadmium telluride. The earlier synthesis method of cadmium telluride is to insert a hot rod into the mixed powder of cadmium and cadmium, and heat it to 500°C to form it. This method adopts the mode of hot rod heating, and the temperature is not uniform enough, and the reaction is not sufficient enough. The Chinese invention patent with the publication number CN1380246A discloses a preparation method of pounded cadmium powder. The method uses cadmium powder and tellurium powder to synthesize in a crucible under vac...

AI Technical Summary

Problems solved by technology

This method adopts the method of heating with a hot rod, the temperature is not uniform enough, and the reaction is not sufficient

The Chinese invention patent with the publication number CN1380246A discloses a preparation method of pounded cadmium powder. The method uses cadmium powder and tellurium powder to synthesize in a crucible under vacuum conditions. The synthesis temperature is to react at the melting point of cadmium. After grinding and annealing, the disadvantage is that the synthesis rate is difficult to guarantee

The Chinese invention patent with the patent number of 200910312590.0 discloses a preparation method of high-purity cadmium telluride. This method is a synthesis reaction in a closed quartz tube coated with carbon, and the cadmium material and tellurium material are alternately put into the quartz tube according to the proportioning ratio. , deoxidize after charging, sinter and seal the tube with bubble sealing, and slowly carry out the synthesis reaction of high temperature and high pressure. Since the conditions of this method are high temperature and high pressure, there are certain risks in the synthesis process, and the industrialization cost is high.

The Chinese invention patent application with the publication number 103420346A discloses a preparation method of cadmium telluride. The method is to put tellurium powder and cadmium powder into the graphite boat in proportion, then place the graphite boat in the quartz tube, and then put the The graphite boat is placed in the synthesis furnace, and the multi-stage heating reaction is carried out first, and then the temperature is lowered in stages to complete the first synthesis, and then repeat the same steps for the second synthesis. This method requires cumbersome loading steps for each synthesis : Put graphite first, then quartz tube, and finally into the synthesis furnace

Moreover, it needs to use quartz tubes for feeding, deoxidation, sealing and breaking quartz tubes to take materials during the synthesis process. Quartz tubes are expensive and cannot be made into other shapes. Each charge is limited and cannot be mass-produced. All need a quartz tube, wasting materials and increasing costs