UA13783U - A method for preparing monocrystals of aggages4 - Google Patents

Abstract

A method for preparing monocrystals of AgGaGeS4, in which method preliminary performed are: batch synthesis of 2-3 g of alloys of a stochiometric composition of AgGaGeS4 during 10-15 minutes, rotation of ampoules with alloys during 45-50 hours at 1220-1270 K and cooling thereof to the room temperature at the rate of 40-50 K/hour for the forced homogenization of alloys, grinding thereof to the powdered state, overloading the charge to the growth ampoule, obtaining homogeneous fusion from them at 1220-1270 K, crystallization of 4-5 mm of fusion and ageing thereof for 90-110 hours for obtaining crystal seed, fusing 2-3 mm of seed, building up monocrystal on the seed.

Description

Description of the invention

A useful model refers to the methods of obtaining single crystals that have semiconductor properties and 2 can be used in optoelectronics and nonlinear optics devices.

AdbSabeb monocrystals) by a set of properties, including significant birefringence, high radiation stability, absence of absorption peaks at the wavelengths of solid-state lasers and the possibility of fulfilling the conditions of synchronism, can be used to create a number of parametric frequency converters (parametric light generators pumped by solid-state lasers, ap-radiation convectors 70 CO" - lasers in the visible range, frequency doublers) Yu.M. Andreev, L.G. Geiko, P.P. Geiko, V.V. Badykov,

S.V. Grechin Optical properties of a new nonlinear crystal AdbSasbeb,) // Applied Physics. - Me2, 2002-

pp. 102-108).

Optical elements of single crystals of different sizes are used depending on their application. For chalcogenide crystals, they can vary within fairly wide limits. For example, for Adsaz o, which is an analogue of AdSabez, according to application, they are from 5хох1 Ohm3.

The method of obtaining single crystals of AdSasbevs is known; |We. M. Apageem, M.M. Ayyspip, M.M. Vaaikom, R.R.

Seiko, M.A. Sogobreiv apa M.O. Reshkpou. Stuzvia! dgomvoi AdSabez, u ogi iShedceps sopmegviop oi TEA SO" Iavzeg//

Te Rocpeepii Ipiegpaiopa! Sopiehepse op o Stuvia! Sgomly ip sopisiop o om/y (pe Tmeschyy Ipiegpaiopai

Sopieegepse op Marog Sgomlypy apa Eriiahu, 9-13 April 2004, Airez Sopodgez, Ogeporie, Egapse: ABvigasiv.-

Sgepobrie, 2004. - p.393), in which single crystals of AdSabez) are grown from the melt of the original components by the method

Bridgman-Stockbarger at a melt movement speed of 14 mm/day, temperature gradient at the crystallization front - bK/mm.

The disadvantage of the known method is that it does not allow obtaining homogeneous crystals of AdbSabez; of large sizes, as "swells" are formed throughout the volume of a single-crystal boule. 29 The closest to the proposed method is the method of obtaining single crystals of AdSacSe from Zea |Mo 28492 A, ShZZ

Ukraine, Bul. Mo5-11, 2000, IPC C30811/00.), which includes the composition of the charge from the elementary components Ad (5.25140g), Ca (3.39436g), Ce (10.60181g), Ze (30.75242g) in accordance with stoichiometric composition, synthesis by the one-temperature AdbSabezzZev method and single crystal growth by the Bridgman-Stockbarger method.

The single crystal growing process is carried out at temperatures: melting zone - 1200-1250K, annealing zone - 750-770OK, annealing time - 200-250 hours. temperature gradient in the crystallization zone - 3-5K/mm, growth rate - about 0.2-0 4mm/h, cooling rate to room temperature - 5K/h.

The disadvantage of this method is the impossibility of obtaining homogeneous sulfur-containing melts and growing from them large single crystals with perfect physical and chemical characteristics. co

The technical task of a useful model is to obtain large perfect Adbasezu single crystals.

The task is solved due to the fact that the method of obtaining AdbCasbez y single crystals includes - the composition of the charge from the elementary components Ad, Ca, se, 5 in accordance with the stoichiometric composition, the synthesis of the compound AdSasezyau in the melt, its crystallization, annealing and cooling to room temperature according to the method

Bridgman-Stockbarger, and a batch synthesis of 2-3 g of alloys of stoichiometric composition "du AdSasbeb5" is carried out beforehand; for 10-15 minutes, rotation of ampoules with alloys for 45-50 hours at 1220-1270K and -o cooling them to room temperature at a rate of 40-50K/h, for forced homogenization of alloys, from crushing them to a powdery state, overloading the charge into the grower ampoule, obtaining from it a homogeneous melt at 1220-1270°C, crystallization of 4-5 mm of melt and holding it for 90-110 hours. for obtaining a crystal seed, melting a 2-3 mm seed, growing a single crystal on a seed at a temperature gradient in the crystallization zone of 1.5-2.0K/mm, annealing zone temperature 850-890K, annealing time - 15 90-120 hours, growth rate 1 ,8-2.2mm/day, cooling rate to room temperature 50-70K/day.

Thus, in comparison with the prototype, the use in the claimed method of the stage of batch syntheses (95) of the starting alloys, their forced homogenization with subsequent grinding to powder, growth of -1 single crystal with preliminary seed formation, reduction of the temperature gradient at the crystallization front, speed growth, annealing time and cooling time makes it possible to grow large, perfect (length up to (ee) 50 4Ω, diameter up to 20mm) crystals of AdSasbez, homogeneous in terms of physical and chemical characteristics. It was established that for the growth of large optically homogeneous single crystals of Adbasbez, the homogeneity of the initial charge, which is achieved by its batch synthesis as described above, is of primary importance. If for the synthesis of batch alloys, the stoichiometric mixture of the starting components will have a weight of less than 2 or more Зg, then the formation of a non-stoichiometric alloy is possible. 59 If the synthesis of batch alloys is carried out for less than 10 min., then the initial components will not react to the end, but for more than 15 min. - the reactions between the initial components are completed.

At a temperature lower than 1220K, the density of the melt is very high, which makes it difficult to homogenize it. At a temperature higher than 1270K, the stoichiometry of the melt is disturbed as a result of sublimation of Seb."

With a rotation time of less than 45 hours. the resulting alloy will not be single-phase, and the duration of rotation will be more than 5 hours. will not change the physical and chemical characteristics of the melt.

If the cooling rate is greater than 50OK/h, cracking of ampoules is possible, and the use of a speed lower than 40K/h will not change the physical and chemical characteristics of the melt.

If the seed size is smaller than 4 mm, the melting process is not possible, and obtaining a seed size larger than 5 mm will lead to an increase in melt costs. because the melting time for seed formation is less than 9 hours. leads to obtaining a large number of small crystals, and more than 120 hours. - will not change its physical and chemical characteristics.

Melting of the 2-Zmm seed is necessary to obtain a perfect surface on which the single crystal is grown.

The amount of melting of the seed depends on its size.

The use of a growth rate of less than 1.9 mm/day will lead to an increase in the crystallization time, and a growth rate greater than 2.2 mm/day will cause the formation of "silts".

The difference between the temperatures of the melting zone and the annealing zone determines the temperature gradient in the crystallization zone. At an annealing zone temperature lower than 850K, the temperature gradient is greater than 2K/mm, and at a temperature higher than 890K, it will be smaller by 1.5K/mm. If the temperature gradient in the crystallization zone is less than 1.5K/mm, then 7/0 does not undergo sufficient diffusional mixing of the melt, and if it is greater than 2K/mm, the formation of "silts" is possible.

If the annealing time is less than 9 hours. or more than 120 hours, then the single crystal will be optically inhomogeneous.

The rate of cooling to room temperature lower than 50OK/day will lead to an increase in cooling time, and higher than 7О0К/day will lead to cracking of the single crystal.

They took 0.57006g of Ad, 0.36847g of Ca, 0.38362g of Se, 0.67785g and filled each of 15 ampoules.

Ampoules were heated until elemental sulfur was completely bound within 1 hour. Forced homogenization of batch melts was carried out at 1220 K for 50 hours of rotation. After cooling to room temperature at a speed of 40 OK/h, the resulting compact alloys were ground to a powdery state and reloaded into a growth ampoule.

A single crystal was grown according to the Bridgman-Stockbarger method at a melt temperature of 1220K 2o. With the preliminary formation of a 4mm seed within 30h, melting of 2mm of it and growth of a single crystal on it at an annealing zone temperature of 890OK, annealing time of OOh, a temperature gradient in the crystallization zone of 1.5K/ mm, growth rate 1.8mm/day, cooling rate to room temperature 5OK/day.

Grown single crystal AdbSabez,; It has a length of 30 mm, a diameter of 2-15 mm, is uniform, without "holes" with a light absorption coefficient in the area of transparency of 0.5 cm! The uniformity of the single crystal was determined.

The proposed method of growing single crystals of Adsabez; can be used both in laboratory and industrial conditions. in

Claims (1)

The formula of the invention of The method of obtaining single crystals of AdbSabeb), which includes the assembly of a charge from the elementary components Ad, Co, Ca, Ce, 5 in accordance with the stoichiometric composition, synthesis of the AdbSabez compound in a melt, its crystallization, h-annealing and cooling to room temperature according to the Bridgman-Stockbarger method, which differs in that a batch synthesis of 2-3 g of alloys of the stoichiometric composition of Adbabevz is carried out beforehand; within 10-15 o From XV, rotating ampoules with alloys for 45-50 hours at 1220-1270 K and cooling them to room temperature at a rate of 40-50 K/h, for forced homogenization of alloys, grinding them to a powdery state, overloading the charge into the growth ampoule, obtaining a homogeneous melt from it at 1220-1270 K, crystallization of 4-5 mm of melt and holding it for 90-110 hours. for obtaining a crystal seed, melting 2-3 mm of the seed, growing a single crystal on the seed with a temperature gradient in the zone " crystallization 1.5-2.0 K/mm, temperature of the annealing zone 850-890 K, annealing time 90-120 hours, growth rate of s 1.8-2.2 mm/day, cooling rate to room temperature 50-70 K/day. ;" Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2006, M 4, 15.04.2006. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. - (95) - And at 50 syu" p. 60 b5