The Secretary of State for Defence in Her Britannic Majesty's Government

The Secretary of State for Defense in Her Britannic Majesty's Government

Secretary of State for Defence in Her Britannic Majesty's Gov. of the

Secretary of the State for Defence in Her Majesty's Government of the

John B Mullin

David John Cole-Hamilton

Anthony Copeland Jones

Stuart J Irvine

Jean Giess

Arthur K Holliday

Deodatta V Shenai-Khatkhate

Paul Webb

Alasdair E McQueen

Neil D Gerrard

John C Hamilton

Philip R Jacobs

Elisabeth D Orrell

Deodattta V Shenai-Khatkhate

Methods for the preparation of a tellurium or selenium compound of formula Ra M Rb wherein M is tellurium or selenium and Ra and Rb are different C.sub.1-20 alkyl, alkenyl or aryl groups are provided in which a compound of formula (Ra).sub.2 M.sub.2 is reacted with a compound of formula (Rb).sub.2 M in each compound M being the same. Compounds of formula RaMMRb may also be isolated as an intermediate. Ra M Rb compounds are useful as precursors for metal organic vapor phase epitaxy processes.

Method for preparation of organo-tellurium and selenium compounds

Method for purification of tellurium and selenium alkyls

Method for preparation of dialkyl tellurium and dialkyl selenium

A method of growing an epitaxial crystalline layer on a substrate which comprises the steps of

Method of growing crystalline layers by vapor phase epitaxy

Preparation of Group II metal alkyls

A layer of Cd.sub.x Hg.sub.1-x Te is grown on the surface of a substrate by decomposing alkyls of cadmium and telluride in a mercury atmosphere. The substrate is placed in a vessel containing a mercury bath with the vessel and bath at a suitable pressure and a temperature below the alkyl decomposition temperature. Hydrogen is passed through bubblers separately containing alkyls of cadmium, telluride and, if required, a dopant into the vessel. The substrate is independently heated above the temperature of the vessel so that the alkyls decompose on the substrate. The substrate may be CdTe, a II-VI compound or mixed II-VI alloy. The alkyls may be dimethyl cadmium, diethyl cadmium, dipropyl cadmium, dimethyl telluride, diethyl telluride, dipropyl telluride, dibutyl telluride etc., or hydrogen substituted tellurium alkyls such as hydrogen ethyl telluride etc.

Manufacture of cadmium mercury telluride

A method of producing a trialkyl gallium compound (R.sub.A).sub.3 Ga, where R.sub.A is selected from methyl and ethyl, includes the step of reacting a gallium trihalide with a Grignard reagent of formula R.sub.A Mg Q, where Q is a halogen, the reaction being carried out in the presence of an ether of the formula R.sub.1 R.sub.2 O having a boiling point at least 50 Celsius degrees above that of the trialkyl gallium compound (R.sub.A).sub.3 Ga, wherein R.sub.1 and R.sub.2 are organic radicals at least one of which has at least 5 carbon atoms. The organic radicals R.sub.1 and R.sub.2 may be aromatic and/or aliphatic radicals. They are preferably alkyl or phenyl radicals. Preferably R.sub.1 R.sub.2 O is an ether having a boiling point more than 100.degree. C. above that of the trialkyl gallium compound. The radicals R.sub.1 and R.sub.2 may each independently have from 1 to 14 carbon atoms but preferably together R.sub.1 and R.sub.2 have between seven and twelve carbon atoms inclusive. Desirably, R.sub.1 R.sub.2 O is di-isopentyl ether (3,3-dimethylpropyl) ether. Other examples of R.sub.1 R.sub.2 O are diphenyl ether and anisole (methylphenyl ether). Preferably, Q is iodine and the gallium trihalide is a chloride.

Preparation of metal alkyls

A method of producing an adduct of an organometallic compound M(R.sup.1).sub.3 where M is either indium or gallium and (R.sup.1).sub.3 represents a plurality of organic radicals which may be the same or different, preferably methyl or ethyl groups, comprising electrolysing, using a sacrificial anode of the metal M, a solution containing components 1 and 2 as follows:

Preparation of adducts

A layer of Cd.sub.x Hg.sub.1-x Te is grown on a substrate by growing layers of HgTe t.sub.1 thick, and CdTe t.sub.2 thick alternately. The thicknesses t.sub.1 and t.sub.2 combined are less than 0.5 .mu.m so that interdiffusion occurs during growth to give a single layer of Cd.sub.x Hg.sub.1-x Te. The HgTe layers are grown by flowing a Te alkyl into a vessel containing the substrate and filled with an Hg atmosphere by an Hg bath. The CdTe layers are grown by flowing of Cd alkyl into the vessel where it combines preferentially with the Te on the substrate. Varying the ratio of t.sub.1 to t.sub.2 varies the value of x. Dopants such as alkyls or hydrides of Al, Ga, As and P, or Si, Ge, As and P respectively may be introduced to dope the growing layer.

Utilizing interdiffusion of sequentially deposited links of HgTe and CdTe

A method of producing an adduct of an organometallic compound M.sup.1 (R.sup.1).sub.x, where M.sup.1 is a Group II or Group III metallic element and R.sup.1).sub.x represents a plurality of organic radicals, which may be the same or different, x being an integer equal to the valency of M.sup.1, comprises electrolysing, using a sacrificial anode of the metal M.sup.1, a solution containing components A, B and C as follows:

Preparation of adducts which may be used in the preparation of compound

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West Malvern, United Kingdom

John B Mullin