The Influence of Charge Transfer on Ion Emission from NaAu<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript> Film

We have studied transient processes of the thermal ionization of sodium on the surface of NaAu_y semiconductor film under the action of a variable external electric field. It is established that the kinetics of Na⁺ ion current during variation of the external field is determined by the establishment of charge distribution in the NaAu_y film, while the efficiency of thermal ionization of Na atoms is related to the concentration of holes near the NaAu_y/vacuum interface.     

A Method for Reconstructing Spectra of Short-Range Particles in π−-Meson Absorption Reactions

Instruments and Experimental Techniques - A method for reconstructing spectra of short-range charged particles in experimental investigations of stopped-pion absorption by nuclei is described. This...     

Anomalous photoemission threshold in high-T c oxide superconductor with Cs and K submonolayers

The photoemission threshold and photocurrent spectra were investigated for Bi₂Sr₂CaCu₂O₈ crystals with K or Cs submonolayer films. The different films of K or Cs were deposited on the Bi-O surface in the temperature range 80–250 K. We observed an appreciable (up to 0.3 eV) energy shift of the threshold and a strong modification of the photocurrent spectra for different temperatures and submonolayer coverages. The appropriate model of such a phenomena is based on a quasimetallic K or Cs clusters effect and additional 2D-polaronic effect.     

The C 1<Emphasis Type="Italic">s</Emphasis> core level spectroscopy of carbon atoms at the surface SiC/Si(111)-4° layer and Cs/SiC/Si(111)-4° interface

Photoemission studies of the electronic structure of the Cs/nano-SiC/Si(111)-4° nanointerface are for the first time carried out with the use of synchrotron radiation in the photon energy range 120–450 eV. The in situ experiments are conducted in the case of submonolayer Cs coating of the surface of an epitaxial SiC layer grown on the vicinal surface Si(111)-4° by a new method of substrate-atom substitution. Modification of the valence-band spectra and the C 1s and Si 2p core levels is studied. The appearance of Cs-induced surface states, with binding energies of 1.2 and 7.4 eV, and a sharp change in the spectrum of the C 1s core level with the appearance of two additional modes are found. The evolution of the spectra shows that the Cs/nano-SiC/Si(111)-4° interface is formed due to charge transfer from Cs adatoms to surface atoms at terraces and steps of the vicinal surface. It is found that the structure of the C layer is nontrivial and involves energetically different carbon states.     

Thermal ionization of amines controlled by the electric-field-driven transport of alkali metal cations

A method for controlling the yield of ionized products from a heterogeneous reaction of amines on the surface of an Na_xAu_y alloy is proposed, which is based on the effect of a weak electric field on the diffusion of Na⁺ ions.     

Electronic Structure of Molybdenum Oxide Oxidized at Different Pressures

Semiconductors - Electronic structure of molybdenum oxides obtained by the oxidation of molybdenum at an oxygen pressure of 1 Torr (thin film) and air (thick film) was studied. It was shown that a...     

The Electronic Structure of the Cs/<Emphasis Type="Italic">n</Emphasis>-GaN(0001) Nano-Interface

Electronic structures of the n-GaN(0001) surface and Cs/n-GaN(0001) interface with submonolayer Cs coverages were studied for the first time in situ by the photoelectron spectroscopy (PES) method. The spectra of photoemission from the valence band, surface electron states, and core levels (Ga 3d, Cs 4d, Cs 5p) under synchrotron excitation were measured in a range of photon energies within 50–150 eV. Evolution of the spectrum of surface states near the valence-band maximum was revealed by PES during the adsorption of Cs atoms. A metallic character of the Cs/n-GaN(0001) nano-interface is demonstrated.     

Calibration of a multilayer semiconductor spectrometer using α sources

A method for calibrating a multilayer spectrometer using α particles is presented. This spectrometer is composed of successive semiconductor Si(Li) detectors and is used for precision detection of long-range charged particles (p, d, and t) with energies of ～100 MeV. The factors affecting the accuracy of calibration are analyzed. This method is shown to guarantee high accuracy in measuring charged-particle energies.     

Possibility of Obtaining 10Be from Spent Control Rods from Fast Reactors

A method is proposed for obtaining ¹⁰Be from spent fast-reactor control rods. The method is characterized by the fact that it is inexpensive and it can combine the separation of ¹⁰Be with the recovery of expensive ¹⁰B. The method has been tested on BN-600 spent control rods. It is shown that in the process of utilizing wastes from fast reactors it is possible to obtain ¹⁰Be in the amount required for experimental investigations in heavy-ion beams. 2 figures, 3 tables, 6 references.     

Initial stages in the formation of a CsAu surface alloy

Threshold photoemission spectroscopy is used to study the formation of a CsAu alloy during deposition of Cs on an Au substrate. It is shown that both the Cs surface layer and the CsAu near-surface alloy undergo indirect photoexcitation. It is found that the formation of a CsAu alloy is accompanied by a sharp rise (by several factors of ten) in the photoemission current while the photoemission threshold remains almost constant. This behavior is attributed to the formation of a band of electronic states near the Fermi level. Pis’ma Zh. Tekh. Fiz. 24, 48–54 (May 26, 1998)