Effect of the spacer growth temperature on the electrophysical and structural properties of PHEMTs

The effect of the growth temperature of an AlGaAs spacer on mobility μ_e of the 2D electron gas in pseudomorphic AlGaAs/InGaAs/GaAs structures with one-sided δ doping by silicon is studied The structures are optimized so that conduction over the doped layer is absent. In such structures, mobility μ_e increases by 53 and 69% at T = 300 and 77 K, respectively, as the growth temperature of the spacer rises from 590 to 610°C with other parameters and growth conditions fixed. Photoluminescence and X-ray diffraction analyses show that the mobility increases because the AlGaAs spacer crystal structure is improved and the AlGaAs/InGaAs interface becomes sharper.     

Thermodynamic characteristics of metal complexation with 3-[4-iodophenylazo]-2,4-pentanedione in an aqueous ethanol solution

Complexation of metals with 3-[4-iodophenylazo]-2,4-pentanedione (L) in an aqueous ethanol solution at temperatures 298 ± 0.5, 318 ± 0.5, and 318 ± 0.5 K has been studied by the potentiometric titration method. The standard thermodynamic functions of the complexation reaction have been found. They change in the following sequence:

Triple-crystal X-ray spectroscopy of diffuse scattering from tracks

A theoretical model is presented for studying the structure of tracks of charged particles in crystals. Two structurally different track regions are considered: the track proper and its elastically deformed vicinity. A computer program is written for determining the contributions from a track and its elastically deformed vicinity to the experimental diffuse-scattering data and their quantitatively evaluating dimensions and other parameters. The effect of the model parameters on the shape of diffuse-scattering curves is also considered.     

Integral geometry and some inverse problems

Baku. Translated from Sibirskii Matematicheskii Zhurnal, Vol. 33, No. 3, pp. 131–145, May–June, 1992.     

Combined analytical formula for two-center Coulomb and hybrid integrals in the molecular coordinate system

Azerbaidzhan State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, No. 1, pp. 160–161, January–February, 1991.     

Calculation of overlap integrals between slater type orbitals using the fourier transformation

S. M. Kirov Azerbaidzhan State University. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 2, pp. 183–185, March–April, 1989.     

Nontrivial role of the resolution function in the formation of double-crystal X-ray rocking curves

A theoretical analysis of the shape of the resolution function of an X-ray diffractometer in the double-crystal nondispersive scheme for measuring rocking curves has been performed. It is shown that this function, along with the strong narrow central line (corresponding to the characteristic line to which the collimator crystal and slits in the experimental scheme are tuned) always contains an additional weak satellite, corresponding to the neighboring characteristic line. This feature manifests itself in experimental curves as an additional pseudopeak, whose intensity is comparable with the corresponding diffraction scattering intensity from a sample in the fundamental characteristic line, and whose shape and exact position are set by the resolution function in a specific experimental scheme. It is shown that the exact allowance for the angular and spectral distribution of incident radiation in the double-crystal scheme makes it possible to precisely determine the parameters of the structures studied.