Consistency of crystal-lattice parameters and thermalexpansion coefficients in five-component heterostructures based on compounds AIIIBV

The possibility of expansion of the limits of variation in the width of the forbidden band in five component solid solutions of compounds A^IIIB^V with consistency of crystallattice parameters and thermal-expansion parameters of the binary substrate and epitaxial layer is analyzed. Possible regions, and the corresponding character, of variation in composition in five-component solid solutions of compounds A_IIIB^V with simultaneous consistency of the crystal-lattice parameters and thermal-expansion coefficients with the binary substrates are identified.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 59–64, January, 1989.     

On the nonlinearity of the P(V) characteristics of heavily doped semiconductors

The interrelation between the hydrostatic pressure P and the relative change of volume V in heavily doped semiconductors with a band structure containing several non-equivalent minima (A^IIIB^V type) is considered.It is shown that under the electron transition from a low central minimum into “heavy” subsidiary minima the P(V) dependence becomes superlinear.The possibility of the appearance in this case of a spontaneous deformation with a significant electron redistribution between the central and the subsidiary minima is treated.     

Control of the lattice period of semiconducting solid solutions during crystallization from the liquid phase

Expressions have been obtained for estimating changes in the composition and period of the lattice of four-component solid solutions based on A^IIIB^V type compounds due to increases in the concentrations of various components in the liquid phase. Selection of the components of the melt has been performed by varying their concentration; this is the most convenient method for selecting the conditions for crystallization of isoperiodic structures In P/Ga_x In_1–xP_y-AS_1–y.Institute of Electronics Technology, Moscow. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. ii, pp. 89–94, November, 1989.     

Research on AIIIBV materials for optoelectronics in the Institute of Physics and Technology of Materials

Conclusions This paper summarizes the work done on A^IIIB^V materials for optoelectronics in the Institute of Physics and Technology of Materials in the last 5–6 years. Part of this work has an original mark on it, part of it follows recognized ways opened else-where. The author expresses his belief that viable roots have been established for stabilizing and for opening up new directions in this institute and in Romania for the remarkable important A^IIIB^V research.Invited talk at the International Conference on Radiative Recombination and Related Phenomena in III–V Compound Semiconductors, Prague, 4–7 October, 1983.     

Band structure of semiconductors with cadmium thiogallate lattice

The energy band structure of a number of A^IIB^IIIC^VI semiconductors with highly symmetric Brillouin zone points , T, P, N is analyzed by the method of a pseudopotential. It is established that the vertex of the valence band and the bottom of the conduction band are at the point . The values obtained for the forbidden bound width are in satisfactory agreement with experimental results.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 57–64, August, 1979.In conclusion, we are grateful to V. V. Badikov for support of the research and stimulating discussions, and also to A. M. Ratner and V. A. Chaldyshev for fruitful consultations.     

The external photoeffect and a simple band scheme of AVB 3 VII iodide crystals

The external photoeffect was measured on AsI₃, SbI₃ and BiI₃ crystals grown in the gaseous phase from very pure parent materials. The energy necessary for transferring an electron from the top of the valence band to the zero energy level was determined from the position of the long wave-length threshold of photoemission in the first approximation. This energy was approximately the same for all Vb metal iodide crystals, i.e. 5.8 eV. The electron affinities of crystals were determined from the known forbidden band width and from the results of measurements, and a simple band scheme of the crystals was proposed.The fine structure of the spectrum was successfully investigated on BiI₃ crystals, from which it was possible to conclude the existence of exciton levels.Finally, the relations between the forbidden band width, the difference of the electronegativities corresponding to the various compounds and the melting point of A^VB^VII crystals were discussed.The authors' thanks are due to Dr. F. J. Vilesov from the Department of Physics of A. A. danov State University in Leningrad (USSR) for the possibility of measuring the photoelectrical work function.     

Cohesive energy of zincblende (A<Superscript>III</Superscript>B<Superscript>V</Superscript> and A<Superscript>II</Superscript>B<Superscript>VI</Superscript>) structured solids

In this paper we present an expression relating the cohesive energy (E _coh in kcal/mol) of A^IIIB^V and A^IIB^VI semiconductors with the product of ionic charges (Z ₁ Z ₂) and nearest-neighbour distance d (Å). The cohesive energy values of these solids exhibit a linear relationship when plotted on a log-log scale against the nearest-neighbour distance d (Å), but fall on different straight lines according to the ionic charge product of the solids. A good agreement has been found between the experimental and calculated values of the cohesive energy of A^IIIB^V and A^IIB^VI semiconductors.     

Thermal property of binary tetrahedral semiconductors

In this paper we present an expression relating the lattice thermal expansion coefficient α_L (10⁻⁶ K⁻¹) for the A^IIIB^V and A^IIB^VI semiconductors with the product of ionic charges (Z₁Z₂), melting temperature (T_m) and nearest neighbor distance d (Å). The lattice thermal expansion coefficient of these compounds exhibit a linear relationship when plotted on a log–log scale against the melting temperature (T_m), but fall on different straight lines according to the ionic charge product of the compounds. A good agreement has been found between the experimental and calculated values of the lattice thermal expansion coefficient for A^IIIB^V and A^IIB^VI semiconductors.     

Magnetic susceptibility of multinary diamondlike semiconductors

Summary The magnetic susceptibility of some A^IB ₂ ^II C^IIIX ₄ ^VI (A^I=Cu, Ag; B^II=Zn, Cd; C^III=Ga, In; X^VI=Se, Te) diamondlike chalcogenides has been measured at RT. Coherently with the form of the relative A^IC^IIIX ₂ ^VI -B^IIX^VI phase diagrams, their magnetic susceptibility fulfils the sum rule typical of ideal solid solutions. Separate values of the diamagnetic and paramagnetic contributions to total magnetic susceptibility are reported and discussed according to a chemical-bond approach previously described. Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16, 1982.     

Technology and characterisation of GaAsN/GaAs heterostructures for photodetector applications

The nitrogen-containing conventional A^IIIB^V semiconductor alloys, so-called diluted nitrides (A^IIIB^V-N), have been extensively studied recently. Unusual properties of these materials make them very promising for applications in lasers and very efficient multijunction solar cells. This work presents the technology and properties of undoped GaAs_1-xN_x/GaAs heterostructures used as active regions in the construction of metal-semiconductor-metal (MSM) photodetectors. The atmospheric pressure metal organic vapour phase epitaxy (APMOVPE) was applied for growing MSM test structures. Their structural and optical properties were examined using high resolution X-ray diffraction (HRXRD), photoluminescence (PL), and photoreflectance spectroscopy (PR). Chemical wet etching was applied for forming an active region and a multifinger Schottky metallization was used as MSM contacts. Dark and illuminated current-voltage characteristics were measured. Based on the obtained results, the main detector parameters as responsivity and spectral response were estimated     

The theory of infrared dispersion of light in crystals with chalcopyrite lattice

The low-frequency dielectric tensor is calculated for A^IIB^IVC ₂ ^V and A^IB^IIIC ₂ ^VI crystals in terms of the long-wave frequencies of lattice vibrations, corresponding to various orientations of the wave vector. The qualitative shape of the spectrum of mechanical polaritons is obtained. The coefficient of light reflection is calculated as a function of the frequency and direction of propagation for a CdGeP₂ crystal.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 39–43, June, 1978.     

Origin bands of electronically forbidden spectra made allowed by centrifugal distortion

Watson’s theory of pure rotational spectra in nonpolar molecules is adapted to show that, if appropriate symmetry conditions are met, centrifugal distortion can lead to the appearance of the forbidden 0-0 origin band in an electronically forbidden spectrum. The intensity of such bands will be low; in the case of the benzene ùB_2u-¹A_1g system the maximum intensity of the forbidden origin is estimated to be about 10⁻⁷ of that of the 6¹₀ band in the main vibronic spectrum. The prospects for the experimental detection of such weak bands are discussed.     

Effects of neon matrix environment on three vibronic emission systems of PbS

Laser sources have been used to explore three emission band systems of the PbS molecule in solid neon matrices. The D → X emission (origin near 29 630 cm^?1), excited biphotonically, consists of broad bands originating from V′ = 0. With laser excitation tuned into the region of the band system origin near 21 860 cm^?1, the B → X system shows emission narrowing of inhomogeneously broadened absorption. Hot luminescence from the B state is also reported. In the a → X system near 14 625 cm^?1 the intensities of phonon sidebands on the high-frequency side of the zero-phonon lines are found to be very sensitive to laser power. Lifetimes of the a, A, and B states of PbS in solid argon have been measured as 260, 0.95, and 1.8 μsec.     

High frequency and static dielectric constants of zinc blende structured solids

A correlation is presented for the high frequency ε_∞ and static ε_o dielectric constants of A^IIB^{V I} and A^IIIB^V semiconductors with the zinc blende structure. The high frequency ε_∞ and static ε_o dielectric constants can be represented by an empirical linear relation that is a simple function of melting temperature T_m, atomic volume Ω and product of ionic charges (Z₁Z₂). Values of high frequency ε_∞ and static ε_o dielectric constants of A^IIB^{V I} and A^IIIB^V zinc blende semiconductors exhibit a linear relationship when plotted against the k_BT_m/Ω (k_B=Boltzmann’s constant), but fall on two straight lines according to the product of ionic charges of the compounds. The calculated results are compared with available experimental data and previous calculations based on phenomenological models.     

Fianite: A multipurpose electronics material

Fianite-zirconium dioxide, stabilized by yttrium (YSZ) has a unique combination of physical and chemical properties that made it a very promising material for a wide range of applications. In this work, we consider the use of fianite as a bulk substrate and buffer layer for A ^III B ^V epitaxy, and as an antireflection and protective coating for photo detectors and solar cells.     

On kinetic phenomena in semiconducting compounds of AIBIIIC2 VI type with chalcopyrite lattice

A four-ellipsoid model of the vertex of the valence band, proposed earlier for some semiconducting compounds of type A^IB^IIIC₂ ^VI, is examined. The anisotropy of the galvano- and thermomagnetic effects is studied under the assumption of an anisotropic relaxation time and the presence of one scattering mechanism.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 46–51, July, 1973.     

Intrinsic defects in ZnO and GaN crystals

The kinetics of defect formation in the system of a crystal with a nonmetal component in the activated gas phase has been investigated. The data obtained has made it possible to develop physicochemical methods of regulating the defect-formation processes depending on the adsorption—desorption—crystallization equilibrium on the surface of a crystal. A kinetic model of defect formation in the A^IIB^VI and A^IIIB^V compounds is proposed. Results of the kinetic analysis of the intrinsic defects in the ZnO and GaN compounds are presented. The photoluminescence spectra of GaN films annealed in a flow of nonmetal-component radicals (atoms) have been considered. This work was reported at the Vth International Scientific-Technical Conference on Quantum Electronics, November 22–25, 2004, Minsk, Belarus. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 760–765, November–December, 2005.     

Kβ2 X-ray emission bands of Ga and As and their compounds

Ga and As Kβ₂ emission bands of the compounds under study consist of a more or less pronounced Kβ₂ main band, a short-wavelength side band which according to calculations by the ‘sudden approximation’ method may be essentially assigned to a KM_IV,V → M_IV,VN_II,III satellite, and long-wavelength 3d → 1s bands. Compounds such as Ga₂(SO₄)₃, Ga(NO₃)₃, Ga₂O₃, NaH₂AsO₄, K₃AsO₄, and As₂O₃ also show long-wavelength side-maxima at a distance of about 12 and 15 eV, respectively, from the main band, which are due to electron transitions from bands or levels with a preponderant 0 2s character.The Kβ₂ main band of A^IIIB^V compounds is less pronounced owing to the widths of the K levels and to instrumental distortions. The distance between the maxima of the state density of the upper valence bands can be recognized only by a shoulder or asymmetry of the band at the long-wavelength side. By calculation of the Ga and As Kβ₂ bands in GaAs with a pseudopotential kp band structure method, and allowing for the influence of both the transition probability and instrumental distortion excellent agreement with experiment is obtained.     

Chemical shift of the Ga and As Kα1,2 and Kβ1,3 X-ray emission lines

By means of a double crystal spectrometer and a computer the chemical shifts of the Ga Kα_1,2, As Kα_1,2 and Kβ_1,3 lines were determined with high accuracy. An interpretation of the results obtained with a free ion model and a calculation according to the Hartree method shows agreement of the values calculated for the effective atomic charges with those based on chemical experience, and also the presence of a charge transfer from the A atom to the B atom in A^IIIB^V compounds. The existence of binding charges is one of the reasons for the fact that |q_A| ≠ |q_B|. The interpretation of the Kβ_1,3 and Lα shifts shows the limitations of the free ion model.