Photoelectric and x-ray dosimetric properties of TlGaS<Subscript>2</Subscript>〈Yb〉 single crystals

The photoelectric properties of TlGa_1?xYb_xS₂ (x = 0, 0.01) single crystals are investigated. It is established that partial substitution of ytterbium for gallium leads to (i) an increase in the electrical resistivity of the samples, (ii) a shift in the maximum of the intrinsic photocurrent toward the long-wavelength range of the spectrum, (iii) a considerable broadening of the spectral sensitivity range, and (iv) an increase in the amplitude of the extrinsic photocurrent. Analysis of the x-ray dosimetric characteristics of the TlGa 1?xYb_xS₂ single crystals demonstrates that, upon partial substitution of ytterbium for gallium in TlGaS₂, the x-ray sensitivity coefficient increases significantly and the current-dose characteristics ΔIE, 0 ～ E^α tend to linearity (α = 1) at low dose rates (E, R/min) of soft x rays. At high dose rates of hard x rays, α tends to 0.5 for both undoped and ytterbium-doped TlGaS₂ single crystals.     

Conduction through localized states in a single crystal of the TlGa<Subscript>0.5</Subscript>Fe<Subscript>0.5</Subscript>Se<Subscript>2</Subscript> alloy

Layered single crystals of the TlGa_0.5Fe_0.5Se₂ alloy in a dc electric field at temperatures ranging from 128 to 178 K are found to possess variable-range-hopping conduction along natural crystal layers through states localized in the vicinity of the Fermi level. The parameters characterizing the electrical conduction in the TlGa_0.5Fe_0.5Se₂ crystals are estimated as follows: the density of states near the Fermi level N_F = 2.8 × 10¹⁷ eV^?1 cm^?3, the spread in energy of these states ΔE = 0.13 eV, the average hopping length R_av = 233 Å, and the concentration of deep-lying traps N _t = 3.6 × 10¹⁶ cm^?3.     

Exciton characteristics of Tl1−x CuxInS2 single crystals

The absorption spectra of Tl_1?x Cu_xInS₂ single crystals (x=0; 0.005; 0.010; 0.015) are interpreted using experimental data. The allowed interband direct transitions are determined, and the energy gap, binding energy, temperature-shift coefficient, Bohr radius, and reduced effective mass of the exciton are estimated.     

Stereochemistry of protonation and mercuration of trisubstituted double bond during cyclization of isoprenoids

Conclusions Initiation of the reaction for the cyclization of isoprenoids by acids proceeds as a nonstereospecific process at the 2,3 bond, while when this reaction is initiated by mercury salts it proceeds as a stereospecific reaction.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1151–1153, May, 1973.     

Stereospecific addition of sulfur-containing electrophiles to a trisubstituted double bond

Conclusions On the example of the reaction for the cylization of the D₃-analog of geranic ester under the influence of sulfur-containing reagents it was shown that the addition of these reagents to a trisubstituted double bond is stereospecific.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1349–1351, June, 1973.     

Current Relaxation in TlGa1 – xDyxSe2 (x = 0.01, 0.03) Single Crystals

Physics of the Solid State - The low-temperature relaxation processes in TlGa1&nbsp;–&nbsp;xDyxSe2 (x = 0.01, 0.03) single crystals have been studied experimentally. The physical...     

Charge transfer and thermopower in TlGdS<Subscript>2</Subscript>

The temperature dependences of the dc conductivity and thermoelectric coefficient of TlGdS₂ in the temperature interval of 77–373 K have been studied for the first time. It has been found that, at low temperatures (114–250 K), the compound has conductivity of the p-type and charge transfer in its energy gap follows the hopping mechanism. The main parameters of localized electronic states in the energy gap have been determined.