ALBERT

Notes: Abstract A new method has been developed for separating a signal consisting of several exponentials into its separate components. Modeling has been carried out for two exponentials with close-lying time constants and with amplitudes of the same order of magnitude. The method possesses high resolution.

Notes: Abstract An investigation was made to determine how a regular relief on the silicon surface influences gettering in silicon-silicon-dioxide structures. The regular relief was created by a photolithographic technique before oxidation and comprised an orthogonal network of overlapping bands. The gettering was determined from the isothermal relaxation of the capacitance of a silicon-silicon-dioxide structure after switching from strong inversion to even stronger inversion. It is shown that a regular relief at the silicon-silicon-dioxide interface is an effective getter at a depth of several hundred micron.

Notes: Abstract Deep-level centers in GaAs-based p-n junctions, which were fabricated by a liquid phase epitaxy in hydrogen or argon ambients, were investigated. The minority charge carrier lifetime for p-layers grown in hydrogen is an order of magnitude larger than that for p-layers grown in argon. It is demonstrated that disimilar deep-level centers are formed in different gas media. Two types of deep-level centers, which act as hole traps, are found in the samples grown in hydrogen. The Arrhenius dependences for these centers are close to known dependences for HL2 and HL5 centers, suggesting that the centers observed can be identified as HL2 and HL5 centers. One type of deep-level center, which is a hole trap, is found in the samples grown in argon. This center is identified as arsenic in the gallium sublattice.

Notes: Abstract A method for determining the energy spectrum of charges and surface-state densities at the interfaces of semiconductor-insulator-semiconductor structures was developed; the method is based on the analysis of capacitance-voltage characteristics. The method was experimentally tested with Si-SiO2-Si structures prepared by direct bonding of both mirror-polished smooth wafers and wafers with a regular mesoscopic relief pattern at the inner surface of the wafers to be bonded. The density of surface states is lower at the surfaces with a regular relief pattern than that at the surfaces without the surface relief.

Notes: Abstract Existing diagnostic techniques used to evaluate the temporal instability of the parameters of a semiconductor-insulator interface with deep-level centers are analyzed. A method is proposed for evaluating temporal instability according to the long-term isothermal transient behavior of the capacitance of a metal-insulator-semiconductor structure. The energy spectrum of the effective density of surface states is determined for n-type InP-SiO2-Al structures prepared by chemical vapor deposition. The variation of the capacitance during long-term isothermal relaxation provides a criterion of temporal instability of a semiconductor-insulator interface.

Notes: Abstract The constant capacitance method with measurement of the voltage-time dependence over a long period of time is used to determine the profile of the density of deep-level centers in an insulator at an interface with a semiconductor. The distribution of deep-level centers in silicon dioxide near an interface with indium phosphide is measured. It is shown that the density of deep-level centers does not depend on the coordinate at distances in the interval 22–27 Å from the interface.

Notes: A triple-axis spectrometer for high-energy ((approximately-greater-than)150 keV) synchrotron radiation has been constructed and characterized. The reciprocal space resolution function of this instrument has been measured using perfect silicon crystals as monochromator, sample, and analyzer. It was found to have dimensions of 1.0×10−5 A(ring)−1 and 2.3×10−4 A(ring)−1 in the directions perpendicular and parallel to the momentum transfer Q, respectively, comparable to those achievable using standard 8-keV triple-axis instruments. The large penetration depths of high-energy x-ray photons, combined with the high instrumental resolution, opens new possibilities in the study of truly bulk condensed matter systems.

Notes: Resonant filtration of synchrotron radiation has been proposed as a method of obtaining x rays with extremely narrow bandwidths (or very long coherence lengths). Resonant scattering of x rays and neutrons is of general interest, and displays several phenomena, which require novel instrumentation in order to be properly observed. We describe here some of the techniques which we have developed for the specific purpose of studying dynamical diffraction by the Mössbauer resonance in 57Fe.

Notes: Spin resolved resonant Raman scattering measurements in Gd metal made by exciting x-ray resonant Raman scattering with circularly polarized x rays near the LIII edge of Gd are presented. The incident photon energy was fixed at the peak of the 2p→4f quadrupolar transition, and the scattered photon was energy analyzed around the 3d→2p fluorescent energy. Asymmetry ratios in the scattered intensity much larger than that of the LIII XMCD effect (x-ray magnetic circular dichroism) were observed upon reversal of the magnetization of the sample or the helicity of the photon. A detailed comparison of these results with XMCD results from both the MIV,V edges and LIII edge of Gd metal will be discussed. © 1996 American Institute of Physics.

Notes: It is only within the last two years that the published United Kingdom accounts have been extended to include sector financial accounts; their use for market analysis is, therefore, still in its infancy.The sectors and sub-sectors distinguished in the financial accounts agree very closely with those recommended by the Working Group on Financial Statistics of the Conference of European Statisticians. A major difference is that in the United Kingdom accounts particular emphasis is placed on the distinction between the public sector and the private sector. For this purpose the public sector consists not only of general government but also includes public corporations (that is, public non-financial corporate enterprises). The classification of assets and liabilities is based on a general list which is also similar to that developed by the Conference of European Statisticians.Because of the large capital formation of public corporations and local authorities, the public sector is normally a substantial borrower from the pirvate sector, although its borrowing requirements fluctuate considerably from quarter to quarter because of the uneven incidence of tax receipts. The personal sector provides about one-third of the total saving of the economy, much of which is in the form of contractual saving—through life assurance and superannuation funds and the repayment of house purchase loans. No direct information is available about transactions in stocks and shares by the personal sector, but it is estimated that the sector is a very large seller of securities and in recent years its sales have amounted to £700 million a year.One factor which is important in the analysis of financial accounts and which is not shown specifically as part of the system is the rate of interest. The proportion of personal saving going into the different forms of short term assets has tended to vary according to the relative rate of interest received. The rate of interest also affects the pattern of borrowing by public authorities.The United Kingdom prepares short term forecasts of national income and of the balance of payments, and also forecasts of the borrowing requirement of the public sector and of the central government in particular. For internal purposes, forecasts are made of the various ways in which the government is expected to finance its borrowing requirement. These forecasts provide a useful framework for considering monetary prospects and are particularly important for showing the relation between the forecasts of the balance of payments and of government borrowing from domestic sources, especially from the banks.