DE1619979A1 - Braking of single crystals under hydrothermal conditions - Google Patents

Description

ERICH E WÄLTHER

Patent attorney "
Applicant: MV PHiLiPS'AEF

- Äite: PHH- .2161.

1967

"Growing single crystals under hydrothermal conditions."

The invention relates to the cultivation of single crystals from chalcogenides under hydrotherral conditions.

A few examples of such a text procedure have already been described. It has ζ * B. Chalkocite single crystals of (Cu ₂ S) were prepared by treating with aqueous CUGs ffatgSgÖ-four hours at 500 * C in a QuarzampulIe. This gave 3ehr small crystals (O, O5 * "Ji ^

It has also described attempts for the production of zinc sulfide, among others - single crystals, with IftgS and ITa ₂ S ₂ O, - solutions al "Lösungsaittel used. This gave only small Frift "ll" and it was geschloeeen that Lötlichkeit der.Sulf.iititt g * ti9 $ is "why no transport took place and no groaten Crystal · could be grown. ,

To increase the solubility of the sulfide , lan & U application iron has concentrated alkaline solutions * ori * aohlaf «n. Bsi using such soundings *! $ # ■! wrnii on material problem

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ORIGINAL

FHH.

A process has now been found for growing single crystals of various chalcogenides in which the problems mentioned do not arise. This process is based on the use of aqueous hydrogen halide solutions. <

The invention therefore relates, and in particular, to a method for growing single crystals from metal chalcogenides of metal sulfides, which are sparingly soluble in dilute acids at room temperature, on an aqueous solution of the same under hydrothermal conditions, and is characterized in that al3 Solvent an aqueous solution of a hydrogen halide is used.

The hydrogen halide used is preferably hydrogen bromide or hydrogen chloride. The concentration of the acid can vary widely, the use of 2H or 12H solutions is preferred. The reaction temperature is preferably chosen between 300 and 50C ⁰ C.

A particularly important advantage of the process according to the invention is also that reaction vessels are made from ^ uarz can use as in contrast to using alkaline Solutions <4uarz practically not attacked by the acidic solutions, even at the relatively high test temperatures will. One can also carry out "inventive methods in an" old autoclave clad in metal which is resistant to halogen acids at higher temperatures. EiO such metal Ht * .B. an alloy of 25% iridium and 75% platinum.

The method according to the invention is explained at Hand the following examples.

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- ■ '■ - ■ la a i4usrsiäffi |! Ttlis: from- ■ - &&. "55.« ® Aus.ae $ drä?. $ Httieg'se-? V 1.5

me. Wall thickness "« and 1.20 ram Lange -'fcäsi -zur ÄijBShaalssteH © "" (see drawing), 6 »* - 5-.osi ^ 4SfHgS-HBr («? §. »" 61} was filled in and: by immersing the Ämpull Then 18.2 g of powdered CuS were poured into the ampoule and evacuated water üb ° rapult was the ampoule * was used in the autoclave and the free volume What se ^ r.. 'b: e-.9 ti crap'_'{r i6 -7 ml) After removing this ^ water.. 12.1 g of CO ₂ - ■ -.... were brought into the fern of a dry ice pole and the autoclave was quickly screwed a.pressure of about 2400; atm (-gyg.- Kennedy ^ AiuJ.Science. 252. ^ 225., 19 ^ 3. ·: "■

The autoclave was then in: an oven with =. two. Temperatu-i "fen auffTPh ^ izt.- i? R lay there ^ 'not horizontally, but around' about \ ξ °. r inclined to the horizontal, the side with .the, .Schraubyer5chlus &. after, · r <be π. Nifcc-h, - Err e ί A - en de r .. Versuph, a % m nre ra-tu. r; from approx. 4 50 °: C ( ge me s κβ η im Versc '*, 4uB & k-egeI} and .45-0-'C .am. JiodeE », these» temperatures were initially about 15i; maintainedrsl * _i;; dij & Sjer _,.;. .the time should ,; top of Acigulle by 'Abtransporitiern ^ er.eini ^ t>errien> Then τ /, urde di e .- .., tempera turverteilung · changed to that ajn; _Soden; yen des-AutO-kl & a mean temperature = from _44If;.. C herr8chtf _#, on · yerachlusskegel v453 ° C · ■ and during, β "JTA ^ eη held" the ^ Temperätureri the Jieiden.. leesestelle oscillated. · due to accompanying. correspond. Chem.InÄ.Tech. H, 1175 U9ß5 ■}. Mf Sphräee te llung- des, AutA-klaven promotes * = Vi ^ i of this temperature distribution the convection and thus the material transport in the Arcjmlle

PHH. 2161

The furnace was switched off to end the experiment and after cooling to room temperature (approx. 24 hours) the autoclave is opened. The vial contents were frozen in liquid air and the ampoule destroyed. Past the entire original soil body (CuS) was in the form of small plates up to 10x6x0.7 mm in the upper part of the ampoule and could by washing with water and Extraction with pyridine (to remove sulfur and CuBr) isolated will.

2. Breeding of red hexagonal HgS.

In a similar experiment to cultivate red HgS (conversion point HgS (red) to HgS (black) is approx. 340 ° C) the day volume of the quartz vial was 13.9 ml, the filling of 2N HCl 6.84 ml (corresponds to $ 56 dee free volume) and the at HgS 17tOg. The filling was carried out in the same way as described above. The free volume of the autoclave was 17 »2.ml, the amount of CO _{2 was} 12.4 g. (corresponds to about 1200 atm at 32Ö ^C C). During the temperature treatment in the inclined autoclave for eight days at the (constant, non-oscillating) temperatures of 330 ° C (bottom) and 31 ^ ⁰ C (Verechlues cone), crystals d3s hexagonal (red) HgS formed in the whole tube, preferably at the top up to about 4ic4xt, 5 mm in size. ·

3. Breeding of Sb., 3 »and SbSBr.

A test for the cultivation of Sb ₂ S, crystals (Graueptessglan ») ran in an ampoule with a content of 12.0« 1 and a filling of 6.38 ml of 48? K HBr (approx. 6V) and 10.0 g Sb ^ S- * 2.15 el from. The free volume * of the autoclave was _{21.0 ml, the amount * n CO 2 was} 15 * 3 g (corresponds to about 2400 atm at i ^ O'C). »After a treatment during Bioben days at 45O * C (soil) or 450 * C (Veröchluaskefel) and

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PHK. 2161

cool to room temperature for about 24 hours there were large crystals of Sb ₂ S (up to 10 mm long needles) and compact material in the tip of the ampoule, and in the remaining parts of the ampoule needles of SbSBr (up to 6 nm long needles of 0 , 2 - 0.4 in diameterJ.

Similar results have also been found for other metal chalcogenides Crystals grown »In the table are the most important Data summarized.

S ^ bstiinss CuS solvent Temperatures "C cone Crystal size in mm. CuSe 6N HBr Jfloor 43O ^e C 1OxSsOtJ ^Cü i, a ³ 6N HBr 450 ° C 340 ° C 6x4js3 ^Cu i, e ^Se 6N HBr 36O ⁰ C 450 ° c 5x5k5 HgS (rotj 6H HBr 45O * C 34O ⁰ C 2% 2 & Z Hg ₅ S ₂ Cl ₂ 28 HCl 36O * C 4x4x0.5 SnS T2N HCl 33O * C 440 * 6 3 * 3x5 '' ■ '' ■■ Sn ₂ S ₃ 2H KCl 450 "C 45O * C CdS 2K HCl 480 ° C 450 ⁰ C $ a0 _? 4s0 ₉ 4 PbS 6K HCl 480 * C 450'C Sb ₂ S usid "SIsSB? - • 12K HCl 4eO * C 45O * C 4s4s4 ' (M HBr 460 ⁹ C 45O ^a e 4 50 * C

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BAD ORIQtfiAL-

PHH. 216t

They show crystals because of the low growth temperature a high degree of order. Therefore, like CdS, they are suitable e.g. for piezoelectric measuring devices such as the acoustic amplifier. SbSBr is a ferroelectric and a photo conductor at the same time excellent sensitivity interesting.

You have the option of using the method as invented Experimental vessel using a quartz vial »has become a very simple execution form of the procedure. Here, a melted-off 4 uarzampulle containing the reaction gel is in placed in an autoclave. The autokiair came - then just closed.

When carrying out the experiment, the temperature is up to 500 * 0 *. A pressure of a few veneered atmospheres is created in the aqueous solution of the ampulla. That is why meß-ia autoclaves maintain a counterpressure that exceeds that of the Quwzaapulle «do so the ampoule keep it safe» Terfehreia are known where the blessing jerk is generated by water * Bebet is usually the inside of the «autoclave via a MmpillKreystes a Konpreanor in connection. In this process, corrobasics appear in the seal ».

it has been shown that the required · bridge is inside · ~ Ä # o 4i »* ®te2s * w e can be remedied very easily by CO ₂ . Here, a g®e, ipi'3t g'aforste · · piece solid IohJ "r.äioxid (dry ice) in the / iiitokla / ®η brought ₈ neehde.i ät ^ & ^ isf aifftille introduced 'as Fe atm etafefIi" w ^ a-'S?., .- * »** wwräfess» a

^ uf.t ümw A «S8s * tiw« it erüV2 | fi «leis«. Simply · 9 _e ift · i «t $ \ fracktr _a * i * * te"% «r« el «» » um su cyyeichen,

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that everyone was walking around during the meeting

The external pressure tempers the internal pressure in the ampoule

and does not exceed the bridge permitted for the autoclave is exceeded.

G0S & 13/1474

Claims (6)

PHK. 2161 'ΊΒ1'9979 PACKAGE PRESENTATIONS: 1. Process for growing single crystals from metal shell ¹ ι cogenides, and especially from diluted at room temperature Acid drilling-soluble metal sulfides, from an aqueous solution of the same under hydrothermal conditions, characterized in that an aqueous solution of a hydrogen halide is used as the solvent. 2. The method according to claim 1, characterized in that an aqueous solution of hydrogen chloride is used as the solvent. ₍ · 3. The method according to claim 1, characterized in that an aqueous solution of hydrogen bromide is used as the solvent. 4 · Process according to claims 1 - 3 »characterized in that that as a solvent an aqueous solution of concentration 2 to 12M of hydrogen halide is used. 5. The method according to claims t - 4, characterized in that a ^ uarzaapulle is used ale Vtrauchsgefäß. 6. The method according to claim 5, characterized in that the ^ uarzaapulle is introduced into an autoclave in which an external pressure is generated, which is greater than the internal pressure in the ampoule during the process, and that this autsend is generated in a jerk by carbon dioxide, the adapted in Fora of dry ice in the required amount of external pressure _r vo closing in the autoclave is introduced " : BATH 009813 / U74