Zinc and Cadmium Chalcogenides
Development of the Environmentally Safe Manufacture Technology of Crystalline Materials Based on Zinc and Cadmium Chalcogenides for IR Opto-electronics
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
8 Project completed
Senior Project Manager
Lapidus O V
Vavilov State Optical Institute (GOI), Russia, St Petersburg
- VITCON Projectconsult GmbH, Germany, Jena\nSOREM , France, Uzés\nCEA / DTA / CEN Grenoble, France, Grenoble\nInstitut de Chimie de la Matière Condensée de Bordeaux, France, Pessac
Project summaryIn this project it is proposed to use research potential of Scientific Center "S.I.Vavilov GOI" and its achievements in the field of optical materials for development of environmentally safe manufacture technology of crystalline materials based on chalcogenides of zinc and cadmium for use in IR optoelectronic devices And in particular(personally), in medical diagnostic thermovision systems, navigating devices, suitable for operation in conditions of bad visibility, in ecological monitoring devices, used for detection of heat losses in buildings, and also by search latent (for example, underground) fires.
At present, methods of physical vapor and chemical deposition are used for manufacture of IR materials based on metal chalcogenides (zinc sulfide and selenide).
Physical vapor deposition (PVD) method (vacuum sublimation of ZnSe, for example) enables to produce high-transparent optical material but with deficit of mechanical strength. It is possible to raise the bending strength limit of polycrystalline optical materials through reduction of grain size. Durability of an optical material in 1,5 time large is in this case reached, than in the first case. One way of doing this is to grow the ZnSe polycrystals by (CVD). However, the method chemical vapor deposition is extremely dangerous because of necessity of application toxic gaseous and explosive reagents (hydrogenselenide, hydrogensulfide and hydrogen) as initial products. The complex and expensive equipment and special equipment for absorption toxic gaseous of products of reaction is required for organization of manufacture of materials with application of a method of chemical vapor deposition.
The ways of crystallization of metal chalcogenides from a solution in easily melting metals or alloys (tin, bismuth, gallium and others) are known also. These methods do not require application toxic gaseous or explosive initial products and come true in closed space without allocation gaseous of products and are environmentally safe from this point of view.
The crystallization from a solution in metals allows to growth both monocrystal epitaxyal film and metal halcogenides polycrystalline layers with the very small size of a grain and, hence, with high mechanical durability. Besides this method allows to receive a material with high chemical cleanliness from extraction of impurity of all heavy metals from a growing crystal in melt; thus it is possible also selective doping of a material by this or that impurity, that it is important at development of semi-conductor devices and LED's on a basis of epitaxyal structures.
In the given work it is supposed to develop ecologically pure technology of obtaining of crystal materials on a basis chalcogenides of zinc and cadmium for optoelectronics of IR range, using methods crystallization from solutions in metals.
It is expected that crystallization from metals-solvents will enable to greatly simplify the equipment, compared with the known method of chemical vapor deposition and will ensure manufacture of finer-grained, and thereby mechanically stronger material, than that produced by physical vapor deposition.
As a result of the work samples of polycrystalline optical IR materials with increased durability (up to 40MPa in a case ZnSe), epitaxyal layers ZnSe-Cr for tunable IR-lasers, LED's on basis of zinc selenide, luminescent in visible area of a spectrum with efficiency about 10-3 quantum/electron will be received.
Potential role foreign collaborators
Foreign collaborators are necessary for realization of tests of new materials and development of the specific requirements to optical materials, used in ecological monitoring devices (tunable IR- laser), for medical engineering (dental-laser) and opto-electronics of visible and IR- range.
Firms VITCON (Germany, fax 16.07.96.) and SOREM (France, fax 21.06.96.) are going to use in developed devices new materials:
- ZnSe, Cr for tunable IR-lasers (analyzer and dental laser),
- ZnSe -LED's (visible range optoelectronic),
- Crystal optical materials of a FR-range with increased strength.
The faxes from prospective collaborators are applied.