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Registration Number

0217U003084, 0112U005082 , R & D reports

Title

Defect formation and kinetic effects in the irradiated and thermally treated semiconductors and nanostructures on their basis

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Head

Gaidar Galyna Petrivna,

Registration Date

17-01-2017

Organization

Scientific Center "Institute for Nuclear Research" of National Academy of Sciences of Ukraine

Description

The LED GaP radiative recombination spectra were investigated. The nature of separate lines is found out. It is shown, that gamma-quanta and 1 MeV electrons irradiation introduces non-radiating levels of radiative defects, which causes glow degradation. It is revealed that the exciton radiated emission which caused by bounded to atom of nitrogen exciton annihilation, shows the raised sensitivity to the radiation compared with others spectral lines. It is shown that the long-term conductivity relaxation of irradiated GaP by electrons with 1 MeV energy is mainly caused by point defect clusters with diameter of 40 - 65 angstrom and potential barrier height of 0,6 - 0,95 eV. Relaxation defects are annealed at 300 ^oC. The recovery of the irradiated sample conductivity occurs at 500 ^oC. Modern methods of computer simulation allow calculating the creation energy of lattice defects and their changes caused by external factors. The molecular dynamics method was used to study main parameters of radiation defects in GaP: threshold energy of defect formation E(sub d) and the energies of formation of a vacancy, a double vacancy, vacancy cavities, penetrating atoms, and antistructural defects. Values of threshold shift energies of P and Ga atoms were obtained from the experimental data obtained on the electron-irradiated crystals, namely: using changes of the initial velocity of carrier removal and decreasing of the emission intensity of a bound exciton. The obtained values of E(sub d) correlate with the results of the computing modeling. It was shown that in the LED GaP the effect of low doses was observed when irradiated with alpha-particles by dose of 10^12 cm^-2. This effect manifests itself in the form of "improving" of the parameters: an increase in capacitance of p-n-junction at room temperature and the magnitude of the differential resistance of current-voltage characteristic, the reduction in the potential barrier between the areas. Identified features are caused by nuclear reactions with alpha-particles and high levels of ionization, as a result of which there are more donors. In the conditions of high levels of excitation of the electron subsystem of the crystal the effect of radiation-stimulated gettering defects can also create the significant contribution into the structural ordering of the transition region.

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Анохін Ігор Євгенович
Барабаш Людмила Іванівна
Верцімаха Ганна Віталіївна
Гайдар Галина Петрівна
Зінець Олег Сергійович
Кібкало Тетяна Іванівна
Ластовецький Володимир Францевич
Литовченко Петро Григорович
Полівцев Леонід Андрійович
Сугаков Володимир Йосипович
Тартачник Володимир Петрович