Department of Diamond and Ultrahard Materials

Primary research and technological fields

• Development of high-pressure apparatus and control systems for the synthesis, thermobaric treatment, and sintering of superhard materials.
• Improving the technologies for manufacturing the large diamond single crystals with special properties.
• Improving the chemical vapor deposition (CVD) technique for the polycrystalline and homoepitaxial single-crystal diamond films on the boron-doped diamond substrates.
• Development of technology for the thermobaric treatment of superhard materials.

A principal scope of the department is growing the large diamond single crystals that have no natural analogues: “nitrogen-free” superpure, and semiconductor precisely doped by boron. Self-designed growth units are applied in the research and pilot production.

A promising research direction is further modification of diamond single-crystal films growth technology using a CVD technique.

A universal high-pressure growth unit (model УРС-01/В).		A CVD growth unit (model BJS 150).

Properties of a superpure single-crystal diamond:

• Size - up to 8 mm;
• Low nitrogen concentration 0.5 – 2.0 ppm;
• теплопроводность не менее 2000 Вт/(м·К);
• Wide range of optical transparency from 225 nm to 25 µm;
• High perfection of crystalline structure;
• Low luminescence: 15 – 30 (ratio of the second-order Raman spectrum intensity to background luminescence);
• High specific resistance - up to 10¹² Ohm•cm.

Applications:

• optical windows for powerful lasers;
• gauges for ultraviolet and X-ray radiation, and high-energy particles;
• parts for optoelectronic devices;
• diamond anvils for research of material properties and phase transitions at superhigh pressures (up to 2.5 Mbar);
• heatsinks for electronic devices;
• probes for scanning probe microscopes;
• substrates for homoepitaxial CVD diamond growth;
• jewelry.

Products from superpure single-crystal diamonds

II b-type semiconductor diamond single crystal:

• Size - up to 8 mm;
• Acceptor ionization energy 0.19 - 0.37 eV;
• Wide range of specific resistance 0,1 – 10⁹ Ohm•cm;
• Color - light blue to black.

Applications:

• high-sensitivity temperature gauges;
• Shottky diodes;
• liquid- and gas-consumption gauges for the petrol and gas industry;
• low-inertia heat elements;
• probes for scanning probe microscopes;
• substrates for homoepitaxial CVD diamond growth;
• jewelry.

Products from semiconductor diamond single crystals

а)		б)

Sensible elements of temperature gauges:

a) Matrix of sensible elements of temperature gauges produced from a plate of boron-doped diamond single crystal by a group technique.

b) 0.5x0.5x0.2 mm diamond low-inertia sensible element of a temperature gauge.

Thermobaric treatment designed in the department effects the brown and yellow initial color of several types of natural diamonds with weights up to 20 carats, turning them into colorless, fantasy yellow, green, pink, blue, and orange colors, thereby improving their appeal to consumers.

а)

Effect of thermobaric treatment on the color of natural diamonds

a) Initial color.

b) Color after the treatment.