RU2513930C1 - Method of producing especially pure sulphides of p-elements of group iii - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to inorganic chemistry and specifically to producing sulphides of p-elements of group III, which are promising materials for semiconductor optoelectronic engineering and infrared optics. Sulphides of p-elements of group III are obtained by reacting sulphur and a corresponding p-element in an evacuated quartz ampoule, wherein the p-element is used in form of a corresponding iodide, synthesis is carried out in a two-section ampoule, initial components are placed in the bottom section which is heated to 250-400°C, after which the obtained sulphide is calcined at temperature not higher than 700°C. By conducting synthesis at sufficiently low temperature, the method considerably reduces contamination of the equipment with the material. The highest possible output of the product is 82-97%.

EFFECT: invention enables to obtain especially pure sulphides of p-elements of group III, in which content of transition metal impurities, according to mass spectrometric analysis, is not higher than 0,5 ppm wt.

2 cl, 1 tbl, 3 ex

Description

The claimed invention relates to inorganic chemistry and relates to the development of a method for producing sulfides of p-elements of group III of the Periodic system, which are promising materials for optoelectronic technology and infrared optics and can be used to produce semiconductor and optical materials.

A known method of producing sulfides of p-elements of group III of the Periodic system by the interaction of sulfur and the corresponding p-element in a vacuum quartz ampoule or placed in a graphite crucible [see, for example, Brower. Inorganic Synthesis Guide. T.3 / M .: Mir, 1985. - S. 127, 942].

The disadvantage of this method is the need to use high temperatures, about 1100-1300 ° C for a long time, more than 20 hours, which requires significant energy consumption, complicates the choice of structural materials and leads to contamination of the resulting sulfides with equipment materials.

A known method of producing sulfides of p-elements of group III of the Periodic system by the interaction of the corresponding elements or their oxides with hydrogen sulfide at a temperature of 1000 ° C [see, for example, Brower. Inorganic Synthesis Guide. T.3 / M .: Mir, 1985. - P.128].

Due to the incomplete conversion of the starting oxides and the interaction of sulfides with the equipment material, the sulfides obtained contain a significant amount of oxygen. For example, the resulting gallium sulfide contains not more than 99.7% wt. Ga ₂ S ₃ , which is due to the presence of an oxygen impurity in the form of unreacted Ga ₂ O ₃ and the resulting oxygen-containing gallium compounds, for example Ga ₂ O ₂ S [see, for example, R. Ivanova Chemistry and technology gallium / M .: Metallurgy, 1973. - P.155], which limits, and sometimes excludes, its use for the production of semiconductor and optical materials. In addition, the method involves the use of toxic hydrogen sulfide.

A known method of producing sulfides of p-elements of groups III and IV of the Periodic system by the interaction of acetates and metal oxoacetates in the environment of n-alkanes with hydrogen sulfide released during the interaction of sulfur with alkane, at temperatures of 180-200 ° C [Pat. RF №2112743, publ. 06/10/1998, MKI C01G 1/12]. The output of sulfides is 58-95% of theoretical. An advantage of this method is a lower synthesis temperature. Due to the fact that the method involves the use of organic substances, the resulting sulfides are contaminated with organic impurities, which limits, and sometimes eliminates, their use for the production of semiconductor and optical materials.

The closest in essence and the achieved effect is a method for producing sulfides of p-elements of group III of the Periodic system by the interaction of sulfur and the corresponding p-element in a vacuum quartz ampoule or a graphite crucible placed in it [see, for example, Brower. Inorganic Synthesis Guide. T.3 / M .: Mir, 1985. - S. 127, 942].

As mentioned above, sulfides are obtained at a temperature of 1100-1300 ° C for a long time (20-30 hours), which requires significant energy consumption, complicates the choice of structural materials and leads to contamination of the resulting sulfides with equipment materials. At such high temperatures, quartz interacts with p-elements and their sulfides, which leads to contamination of the resulting sulfides with an admixture of silicon. During the synthesis in a graphite crucible, the resulting material is contaminated with carbon.

The problem to which the invention is directed is the development of a method for producing sulfides of p-elements of group III of the Periodic system, aimed at increasing the degree of purity by reducing the polluting effect of the equipment material.

This problem is solved due to the fact that in the known method for producing sulfides of p-elements of group III of the Periodic system by the interaction of sulfur and the corresponding p-element in an evacuated quartz ampoule, according to the claimed solution, the corresponding p-element is used in the form of iodide, the synthesis is carried out in 2- sectional ampoule, while the starting components are placed in the lower section, which is heated to a temperature of 250-400 ° C, after which the sulfide obtained is calcined at a temperature not exceeding 700 ° C.

It is preferable to carry out the synthesis of sulfides at 350 ° C for 1-2 hours, since within the specified time the maximum possible yield of the product is 82-97%.

The essence of the claimed invention lies in the fact that the corresponding p-element of group III is used in the form of iodide, the synthesis is carried out in a 2-section ampoule, while the starting components are placed in the lower section, which is heated to a temperature of 250-400 ° C, after which the sulfide obtained calcined at a temperature not exceeding 700 ° C. Using as a charge, along with sulfur, iodides of p-elements provides sulfides at a lower temperature of 250-400 ° C, instead of 1100-1300 ° C, according to the prototype. The use of iodides allows the components to be loaded into the reactor by evaporation in vacuum, which reduces the flow of impurities from the atmosphere upon receipt of highly pure substances and materials. The purity of the starting iodides as fusible highly volatile substances can be enhanced by their additional purification. When using iodides, the released iodine interacts with an admixture of hydrogen sulfide and is removed from the melt in the form of hydrogen iodide, which reduces the content of hydrogen impurity in the resulting sulfide.

The synthesis in the lower part of the 2-section ampoule ensures the removal of iodine from the melt and its condensation in the upper (cold) part of the ampoule, which shifts the chemical equilibrium towards the formation of the resulting sulfide.

It was experimentally established that when the lower section of the reactor is heated to a temperature below 250 ° C, the yield of sulfides obtained is quite small and does not exceed 20%, and at temperatures above 400 ° C, significant evaporation of p-iodides occurs and their condensation occurs in the upper section. This reduces the yield of sulfides and leads to a deviation of their composition from stoichiometric. An essential feature is the calcination temperature of the sulfide obtained. It was experimentally established that this temperature should not be higher than 700 ° C. At a temperature not exceeding 700 ° C, the residual amounts of iodine are removed, and at a temperature above 700 ° C, the polluting effect of the reactor material begins to have a significant effect (see B.G. Borisevich, Hydrogen entering the selenium melt from the walls of a quartz container / V.G. Borisevich , V.I. Wojciechowski, V.G. Devyatykh, E.M. Dianov, V.G. Plotnichenko, I.V. Skripachev, M.F. Churbanov // High-purity substances. -1991. -№3.- S. 82).

The content of transition metal impurities in the obtained sulfides according to mass spectral analysis does not exceed 0.5 ppm wt.

The mentioned features are significant, because each of them is necessary, and together they are sufficient to obtain highly pure sulfides of the p-elements of group III of the periodic table.

The advantage of this method is that the iodine released after the end of the synthesis can be used again for the synthesis of metal iodides. Thus, the proposed method for producing sulfides is waste-free.

Example 1

90.000 g of gallium (III) iodide and 9.618 g of sulfur are loaded into the lower part of a two-section quartz glass ampoule. The ampoule is evacuated and sealed along the bypass tube, which makes it possible to re-evacuate it. The lower section of the ampoule with the charge is placed in a vertical furnace and heated to 300 ° C. The released iodine evaporates from the melt and condenses in the upper section. After 2 hours of synthesis, the ampoule is soldered to a vacuum system equipped with a trap with liquid nitrogen, placed in a horizontal furnace and heated to 650 ° C, at which residual iodine is removed. 22.46 g of gallium sulfide are obtained, the yield of which is 96%. The iodine content in the obtained gallium sulfide, according to the results of X-ray spectral microanalysis, is not more than 0.1 mol. % The content of metal impurities according to mass spectral analysis is shown in the table. The table shows that the obtained gallium sulfide is especially pure.

Table. The impurity composition of gallium sulfide.

Element ppm wt. Element ppm wt. N - TO 0.3 Li - Ca 0.6 Be - Sc <0.1 AT <0.02 Ti <0.2 FROM ≤40 V - N ≤3 Cr <0.2 O - Mn <0.2 F ≤0.2 Fe 0.5 Na <0.05 Co <0.2 Mg <0.05 Ni <0.3 Al <0.05 Cu <0.3 Si 7 Zn <1 P <0.1 Ge <0.7 Sn <1.5 As ≤7

Example 2. The experimental conditions, as in example 1, only in the lower part of the two-section ampoules load 90,000 g of aluminum iodide and 10.875 g of sulfur. The lower section of the ampoule with the charge is heated to 350 ° C. The released iodine evaporates from the melt and condenses in the upper section. After 1 hour of synthesis, the ampoule is soldered to a vacuum system equipped with a trap with liquid nitrogen, placed in a horizontal furnace and heated to 700 ° C, at which residual iodine is removed. Get 16.781 g of aluminum sulfide, the yield of which is 95%. The iodine content in the obtained aluminum sulfide, according to the results of X-ray spectral microanalysis, is not more than 0.1 mol.%. According to mass spectral analysis, the content of transition metal impurities does not exceed 0.5 ppm wt.

Example 3. The experimental conditions, as in example 1, only in the lower part of the two-section ampoules load 90,000 g of indium iodide and 8.691 g of sulfur. The lower section of the ampoule with the charge is heated to 400 ° C. The released iodine evaporates from the melt and condenses in the upper section. After 1.5 hours of synthesis, the ampoule is soldered to a vacuum system equipped with a trap with liquid nitrogen, placed in a horizontal furnace and heated to 650 ° C, at which residual iodine is removed. Obtain 24.081 g of indium sulfide, the yield of which is 82%. The iodine content in the obtained aluminum sulfide, according to the results of X-ray spectral microanalysis, is not more than 0.1 mol.%. According to mass spectral analysis, the content of transition metal impurities does not exceed 0.5 ppm wt.

Claims (2)

1. The method of producing sulfides of p-elements of group III of the Periodic system by the interaction of sulfur and the corresponding p-element in a vacuum quartz ampoule, characterized in that the p-element is used in the form of the corresponding iodide, the synthesis is carried out in a 2-section ampoule, while the initial components are placed in the lower section, which is heated to a temperature of 250-400 ° C, after which the sulfide obtained is calcined at a temperature not exceeding 700 ° C. 2. The method of producing sulfides according to claim 1, characterized in that the lower section is heated to a temperature of 350 ° C for 1-2 hours.