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Information × Registration Number 0217U003086, 0112U005082 , R & D reports Title Defect formation and kinetic effects in the irradiated and thermally treated semiconductors and nanostructures on their basis popup.stage_title Head Gaidar Galyna Petrivna, Registration Date 17-01-2017 Organization Scientific Center "Institute for Nuclear Research" of National Academy of Sciences of Ukraine popup.description2 Structural and optical properties of single crystal silicon irradiated with 27.2 MeV helium ions by using fluences more than 10^16 ion/cm^2 were studied at various beam currents. It was found that at currents 0.25 to 0.45 microampere, heavily damaged layers containing voids were formed in ion path in Si and behind it. With increasing the beam current up to approximately 1microampere, the layer structures consisting of voids were observed only in the ion path. The number of layers in the ion path region depends on the beam intensity. It is a combination of high energy and high fluence helium implantation that can form layered structure with voids in silicon, as observed in the experiments. To explain the formation of ordered structures and spread them in the region behind the ion path the concept of mobile solitons, which propagate in the crystal along the densely packed directions, is used. The method of modulation spectroscopy of light electroreflectance in the spectral range 3 - 3.8 eV was used in order to study optical and electronic properties, and also inner mechanical stresses of oxygen reach (8 · 10^17 cm^-3) silicon, irradiated with fast neutrons (10^15 - 10^18 n/cm^2), annealed isothermally at 800 ^оС and chemically etched. The conditions of appearing of the Franz-Keldysh, the quantum-confinement and the surface gettering effects were established. From the analysis of electroreflectance spectra, the following parameters were obtained: the energy of electron transition (bandgap), the broadening parameter, the energy relaxation time of charge carriers, the intrinsic mechanical stresses, the electrooptical energy, the surface built-in electrical field, the energy of quantized levels and the quantum well width in dependence on the samples treatment conditions. In samples, irradiated by 10^18 n/cm^2, the splitting of electroreflectance signal was discovered with maxima shifts in opposite sides in comparison with the Еg value for initial sample. The revealed high dose effect is caused by the selforganization of own radiation-induced defects owing to existence of two types separated disorder regions (vacancies and interstitials) with the mechanical stresses of different sings. Electroluminescence of green N-doped gallium phosphide light-emitting diodes was studied. The negative differential resistance region in the current-voltage characteristics was found at low temperature (less then 90 K). Possible reason of this phenomenon is the redistribution of the recombination current between the channels of annihilation on the isolated nitrogen atoms and on the NN1 pairs. Product Description popup.authors Анохін Ігор Євгенович Верцімаха Ганна Віталіївна Гайдар Галина Петрівна Ластовецький Володимир Францевич Литовченко Петро Григорович Старчик Маргарита Іванівна Сугаков Володимир Йосипович Тартачник Володимир Петрович popup.nrat_date 2020-04-02 Close