Oleg G. Semyonov

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From the point of view of radiation safety, interstellar space is not empty. Neutral and ionized interstellar gas and cosmic rays consisting of H and He-nucleons constitute radiation hazard aboard relativistic interstellar ships. Relativistic aberration of cosmic rays is evaluated and radiation doses from oncoming relativistic flow of interstellar gas and(More)
We study the photoluminescence spectra of n-doped InP bulk wafers, both in the reflection and the transmission geometries relative to the excitation beam. From the observed spectra we estimate the spatial distribution of minority carriers allowing for the spectral filtering due to reabsorption of luminescence in the wafer. This distribution unambiguously(More)
Recombination of minority carriers in heavily doped n-InP wafers has been investigated using spectral and time-resolved photoluminescence at different temperatures. Studies of the transmitted luminescence were enabled by the partial transparency of the samples due to the Moss–Burstein effect. Temporal evolution of the transmitted luminescence shows(More)
We describe the design, properties, and performance of an excitation-emission (EE) fluorimeter that enables spectral characterization of an object simultaneously with respect to both its excitation and its emission properties. Such devices require two wavelength-selecting elements, one in the optical path of the excitation broadband light to obtain tunable(More)
We study the photoluminescence spectra excited at an edge side of n-InP slabs and observed from the broadside. In a moderately doped sample the intensity drops off as a power-law function of the distance from the excitation—up to several millimeters—with no change in the spectral shape. The hole distribution is described by a stationary Lévy-flight process(More)
We study the spatial distribution of minority carriers arising from their anomalous photon-assisted diffusion upon photo-excitation at an edge of n-InP slab for temperatures ranging from 300K to 78K. The experiment provides a realization of the “Lévy flight” random walk of holes, in which the Lévy distribution index γ is controlled by the temperature. We(More)
The shape of the photoluminescence line excited at an edge face of InP wafer and registered from the broadside is used to investigate the intrinsic emission spectrum. The procedure is much less sensitive to the surface properties and the carrier kinetics than the conventional methods used with the reflection or transmission geometry of photoluminescence.(More)
Radiative efficiency of highly luminescent bulk InP wafers severely degrades upon heat treatment involved in epitaxial growth of quaternary layers and fabrication of photodiodes on the surface. This unfortunate property impedes the use of bulk InP as scintillator material. On the other hand, it is known that thin epitaxial InP layers, grown by molecular(More)
Broadband reduction of light reflection from the surface of InP wafers after high-temperature annealing in air has been observed. In the transparency region of the material, the reflection drop is accompanied by increasing transmission of light through the wafer. The spectral position of a deep minimum of the reflection coefficient can be tuned, by varying(More)
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