Nature of E c −0.37 eV centers and the formation of high-resistivity layers in n-type silicon

The DLTS and Van der Pauw methods are used to investigate the production of E _c −0.37 eV centers responsible for the formation of high-resistivity layers in n-type Si irradiated with electrons and annealed in the temperature range 80–320 °C. An analysis of the experimental data leads to a conclusion as to the composition of the E _c −0.37 eV centers ([V-O-C]) and to the conclusion that their formation is stimulated by a flux of interstitial atoms away from the interface into the interior of the semiconductor during annealing accompanied by the reactions: 1) I+C_s→C_i,C_i+[V-O]→[V-O-C] (dominant reaction); 2) I+V ₂→V,V+[C-O]→[V-O-C]. Fiz. Tekh. Poluprovodn. 31, 993–997 (August 1997)     

Spontaneous and stimulated emission from CdxHg1−x Te semiconductor films

The experimental data on observation of spontaneous and stimulated emission from thin epitaxial Cd_xHg_1?x Te films optically pumped by Nd: YAG laser radiation are reported. A simple theoretical model is suggested to describe the initiation of population inversion under these conditions. The parameters realized under the experimental conditions are theoretically estimated.     

Effect of the Sapphire-Nitridation Level and Nucleation-Layer Enrichment with Aluminum on the Structural Properties of AlN Layers

The effect of atomic aluminum deposited onto sapphire substrates with different nitridation levels on the quality of AlN layers grown by ammonia molecular-beam epitaxy is investigated. The nitridation of sapphire with the formation of ~1 monolayer of AlN is shown to ensure the growth of layers with a smoother surface and better crystal quality than in the case of the formation of a nitrided AlN layer with a thickness of ~2 monolayers. It is demonstrated that the change in the duration of exposure of nitrided substrates to the atomic aluminum flux does not significantly affect the parameters of subsequent AlN layers.     

Chloride epitaxy of β-Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> layers grown on <Emphasis Type="Italic">c</Emphasis>-sapphire substrates

The method of chloride epitaxy is employed to grow β-Ga₂O₃ epitaxial layers on a c-sapphire substrate. Purified dry air is used as the source of oxygen. The layers are studied using the methods of X-ray diffraction, optical microscopy, scanning electron microscopy, transmission electron microscopy, and micro-Raman spectroscopy. It is found that the growth plane of the layers is (\(\bar 2\)01), parallel to the substrate surface. The layers consist of separate large crystalline grains of three different in-plane orientations rotated relative to each other in the growth plane by 60°. Misorientation can be caused by the different symmetry of the substrate and the epitaxial layer.     

Nanostructure Growth in the Ga(In)AsP–GaAs System under Quasi-Equilibrium Conditions

Semiconductors - The formation of nanostructures on the surface of GaAs under quasi-equilibrium conditions in a quasi-closed volume from saturated phosphor and indium vapors in the presence of a Au...     

Interaction of surface acoustic waves with a two-dimensional electron gas in the presence of spin splitting of the Landau bands

The absorption and variation of the velocity of a surface acoustic wave of frequency f=30 MHz interacting with two-dimensional electrons are investigated in GaAs/AlGaAs heterostructures with an electron density n=(1.3–2.8)×10¹¹cm² at T=1.5–4.2K in magnetic fields up to 7 T. Characteristic features associated with spin splitting of the Landau level are observed. The effective g factor and the width of the spin-split Landau bands are determined: g*≅5 and A=0.6 meV. The greater width of the orbital-split Landau bands (2 meV) relative to the spin-split bands is attributed to different shielding of the random fluctuation potential of charged impurities by 2D electrons. The mechanisms of the nonlinearities manifested in the dependence of the absorption and the velocity increment of the SAW on the SAW power in the presence of spin splitting of the Landau levels are investigated. Fiz. Tekh. Poluprovodn. 33, 979–985 (August 1999)     

GaInAsSb/GaSb heterostructures grown in the spinodal decay region by liquid-phase epitaxy from Sb-enriched solution-melts

Nearly isoperiodic solitary Ga_1−x In_xAs_ySb_1−y /GaSb heterostructures, in which the composition of the solid solution should be found inside the region of spinodal decay (x⩽0.4), were grown by liquid-phase epitaxy from solution-melts enriched with antimony. On the basis of the results of a study of structural and luminescence properties of Ga_1−x In_xAs_ySb_1−y /GaSb heterostructures we have determined the main conditions ensuring reproducible growth of epitaxial layers, homogeneous in the composition of their solid solutions in the region where the existence of processes of spinodal and binodal decay have been theoretically predicted. It is shown that the magnitude and sign of the deformation which the layer undergoes during growth and also the thickness of the layer are the main factors influencing the properties of the growing GaInAsSb solid solutions in the spinodal-decay zone. Fiz. Tekh. Poluprovodn. 33, 1134–1136 (September 1999)     

Magnetic alignment measurements at room and cryogenic temperature of LHC cryodipoles and associated correctors at CERN

Considerable effort is spent at CERN on magnetic alignment measurements of main lattice LHC dipoles, including field direction, curved axis shape and position of in-built correctors, essential to verify the geometry of the assembly and to guarantee correct installation with respect to the reference beam orbit. The current baseline includes measurements of a statistically relevant percentage of cold masses and cryostated magnets before, during and after cryogenic tests. For this, we use a range of scanning probes based either on harmonic coils or fixed coils in AC mode, with laser and telescope trackers to measure position with respect to cryostat fiducials. The dipole is usually powered in "quadrupole mode" to create a convenient magnetic reference. In this paper, we first recall objectives, equipment and methods. Then, we report the status of the test activities, showing results obtained on the first pre-series dipoles, including cross-checks of various measurement systems and correlation between measurements at room and cryogenic temperatures.