Unique features of electrical conductivity in cadmium sulfide crystals irradiated by high-neutron dosages

Irradiation of semiconductors by high-energy heavy particles leads to the formation of defect clusters. The present study will analyze the dosage dependence of dark conductivity () in high-resistance CdS single crystals upon irradiation by fast neutrons. Some parameters of defect clusters in the specimens studied are evaluated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 19–23, February, 1984.     

Characteristics of the influence of electron and neutron irradiation on the fundamental absorption edge and reflection spectra of pure and copper-doped cadmium sulfide single crystals

Irradiation of CdSCu single crystals with fast electrons in a dose of D 10¹⁷ e/cm² resulted in strong broadening and shift (toward lower energies) of the fundamental absorption edge. Moreover, the peak-to-peak amplitudes of the dispersion curves of reflection decreased compared with pure samples which received the same dose. Neutron irradiation produced the opposite effect. For the same radiation doses as in the case of pure single crystals (D 10¹⁸ n/cm²) the fundamental absorption edge and the peak-to-peak amplitudes of CdS:Cu samples were less affected by the irradiation than the pure crystals. The experimental results were explained by the nature of the interaction of the Cu atoms with point and three-dimensional defects formed as a result of electron and neutron irradiation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 37–41, July, 1980.     

Investigation of Concentrator Photovoltaic Modules with Cascade Solar Cells

Technical Physics - The measuring capabilities of a solar radiation simulator and computer simulation have been used in the study of concentrator photovoltaic modules with three-junction solar...     

Photovoltaic modules with cylindrical waveguides in a system for the secondary concentration of solar radiation

The parameters of the concentrating photoelectric modules with triple-junction (InGaP/GaAs/Ge) solar cells whose focusing system contains an original secondary optical element are studied. The element consists of a plane-convex lens in optical contact with the front surface of an intermediate glass plate and a cylindrical waveguide that is located on the rear side of the glass plate above the surface of the solar element. It is demonstrated that the structure of the secondary optical element provides a wide misorientation characteristic of the concentrator and the cylindrical waveguide allows a more uniform radiation density over the surface of the solar cell. The effect of chromatic aberration in the primary and secondary optical systems on the parameters of photoelectric modules is analyzed. It is demonstrated that the presence of waveguides with a length of 3–5 mm leads to effective redistribution of radiation over the surface of the solar cell whereas shorter and longer waveguides provide the local concentration of radiation at the center of the photodetecting area.     

Rearrangement of defects in single crystals of cadmium sulfide irradiated with fast electrons

This study exaines CdS single crystals subjected to a special nonalloying treatment, alloyed with copper, and annealed in a cadmium atmosphere. Irradiation of the test specimens by electrons with E 1.2 MeV led to the formation of mobile defects and to decomposition of the original donor-acceptor associates. Over time, the primary radiation defects form secondary defects which act as fast recombination centers responsible for impurity photoconductivity. New donor-acceptor pairs are formed when the irradiated specimens are stored, these pairs being paramagnetic centers. Conclusions are made as to the nature of the secondary radiation defects, which are distributed both in the body of the specimens and near their surface.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 5–9, May, 1988.     

Formation of defects in CdS and CdS:Cu single-crystals irradiated by E = 46 MeV protons

The results of an experimental study of the spectral dependence of the adsorption coefficient, reflection exciton spectra, luminescence, photoconductivity (in the wavelength range from 0.45 to 1 m), and dark conductivity of pure and copper-doped CdS single-crystals, irradiated by E=46 MeV protons, are presented. It is shown that irradiation produces characteristic defects both in the cadmium sublattice and in the sulfur sublattice, but for one and the same irradiation dosages the defect concentration in CdS:Cu is many times higher than the concentration of defects in the pure crystals. A significant difference is observed in the concentrations of defects in these samples only when they are irradiated by high-energy particles which strongly ionize the lattice of the crystals. It is proposed that there exists an ionization mechanism for the transfer of a significant part of the energy of the moving protons to Cu atoms, which form a large number of defects (more than 1 per copper atom).Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 62–66, May, 1987.     

Electrical, optical, and photoelectric properties of electron-irradiated indium-doped cadmium sulfide single crystals

The effect of irradiation by 1.2-MeV electrons to a dose Φ=2×10¹⁷ cm^?2 on the electrical, optical, and photoelectric properties of In-doped CdS single crystals was studied. The experimental data obtained permit one to conclude that irradiation initiates decomposition of the supersaturated In solution in CdS, with the indium atoms at the sites of the cation sublattice being expelled by cadmium interstitial atoms. New slow-recombination centers were observed to exist in the irradiated CdS: In samples, with the maxima of optical quenching of the photoconductivity lying in the region of $\lambda _{M_1 } = 0.75\mu m$ and $\lambda _{M_2 } = 1.03\mu m$ . It is suggested that the new recombination centers are related to complexes containing cadmium vacancies and indium atoms.     

Beam stability investigation for a free electron lithographic laser based on an energy-recovery linac

According to leading producers of microelectronic devices, lithography based on free electron lasers (FEL) could become the main technology for the mass production of elements with a scale up to 5 nm in the near future. One of the main hindrances in this path is the absence of working FEL with the required parameters. A feasibility study devoted to the production of such an FEL based on a superconducting energyrecovery linac (ERL) has been carried out at the Budker Institute of Nuclear Physics (BINP). The ERL average current is limited by longitudinal and transverse instabilities, caused by the interaction of an electron beam with the fields induced by it in the superconducting cavities. The estimations of the threshold currents and parameters of the ERL required for the operation of FEL are obtained.