V. A. Dravin

Radiation damage in diamonds subjected to helium implantation

Optical spectroscopy and volume “swelling” measurements were used to study radiation damage and graphitization of diamonds implanted with helium ions at temperatures from 77 to 373 K. It is established that the radiation damage decreases as the implantation temperature increases. This effect is explained by radiation-stimulated annealing of defects caused by damaging. It is shown that the result of formation of a graphitized layer is determined not by the implantation dose but by the level of radiation damage. It is found that the lower the implantation temperature, the lower the annealing temperatures required for the formation of a graphitized layer. It is shown that annealing of radiation defects and the formation of a graphitized layer in a diamond occur up to 1600°C.

Diamond–graphite transformation induced by light ions implantation

Abstract Optical absorption, interference and microscopy studies of diamond samples implanted with light ions (H + , D + and He + ) and annealed at various regimes revealed new features of irradiation-induced graphitisation of diamond: ‘low temperature’ graphitisation related to vacancies and the specific mechanism of graphitisation accompanied by blistering in H + -implanted samples. Migration of radiation damage is discussed in relation to the stability of the graphitised layers.

Defect-induced graphitisation in diamond implanted with light ions

Abstract Optical absorption, interference and microscopy studies of diamond samples implanted with light ions (H+, D+ and He+) and annealed at various regimes revealed new features of irradiation induced graphitisation of diamond: the “low temperature” graphitisation directly related to vacancies, the specific mechanism of graphitisation accompanied by blistering in H+ implanted samples and high temperature graphitisation stimulated by residual radiation damage.

Bolometric detector embedded in a polycrystalline diamond grown by chemical vapor deposition

A fast bolometric detector embedded in a plate of chemical-vapor-deposited polycrystalline diamond was developed and fabricated. The working element of the bolometer is a buried graphitized layer (with temperature-sensitive resistance) fabricated in the bulk of a diamond by C+ ion implantation followed by annealing. The kinetics of the response of the structure to irradiation with light from an LGI-21 pulsed nitrogen laser (λ = 337 nm, τP ∼ 8 ns) were studied. The room-temperature response width at half-maximum is ∼ 20 ns. Using the space-time distribution of responses of the structure, thermal (bolometric) signals were resolved from signals of different nature (photoconductivity or photovoltage).

Propagation of acoustic phonons across the interfaces in CdTe and Si/CVD-diamond and quasi-two-dimensional phonon wind in CdTe/ZnTe quantum wells

Using a heat-pulse technique we investigated propagation of acoustic phonons in twinned CdTe, ZnTe crystals, in the vicinity of CdTe/ZnTe quantum well, and Si/CVD-diamond structures. Phonon mean free paths in CdTe were estimated. We studied the effect of phonon wind on the luminescence of narrow CdTe quantum well and observed an increase in the total luminescence intensity and the change of the luminescence band shape. We believe that this effect is due to a quasi-two-dimensional lateral propagation of subsurface and interface acoustic phonons in the ZnTe/CdTe structure. Preliminary data obtained on the Si/CVD-diamond interfaces suggest they are strongly damaged. To reduce the thermal boundary resistance of the interface between the material studied and the thin-film phonon detector we developed a buried bolometer based on a graphitized layer produced by ion implantation in diamond.