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Arsen Subashiev

Bio: Arsen Subashiev is an academic researcher from Stony Brook University. The author has contributed to research in topics: Photoluminescence & Scintillator. The author has an hindex of 10, co-authored 29 publications receiving 243 citations. Previous affiliations of Arsen Subashiev include State University of New York System & Saint Petersburg State Polytechnic University.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors used spectral and time-resolved photoluminescence at different temperatures to investigate the recovery of minority carriers in heavily doped n-InP wafers.
Abstract: 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 virtually no effect of surface recombination but is strongly influenced by photon recycling. Temperature dependence of the decay time suggests Auger recombination as the dominant nonradiative process at room temperature. Radiative quantum efficiency has been evaluated at different doping levels and at 2×1018 cm−3 it is found to be as high as 97%, which makes n-InP suitable for scintillator application.

31 citations

Journal ArticleDOI
TL;DR: In this paper, the shape of the photoluminescence line registered from a side edge of InP wafer is studied as a function of the distance from the excitation spot.
Abstract: The shape of the photoluminescence line registered from a side edge of InP wafer is studied as a function of the distance from the excitation spot. The observed redshift in the luminescence maximum is well described by radiation filtering and is consistent with the absorption spectra. Our method provides an independent and accurate determination of the Urbach tails in moderately doped semiconductors.

27 citations

Journal ArticleDOI
TL;DR: In this article, the effects of patterning the cladding or the core layer of a three-layer optical waveguide on the polarization properties of propagating radiation were examined, where the core material is a semiconductor with optical gain.
Abstract: Uniaxially patterned (UAP) dielectric layers have an optical anisotropy that can be externally controlled. This paper examines the effects of patterning the cladding or the core layer of a three-layer optical waveguide on the polarization properties of propagating radiation. Particular attention is paid to the case when the core material is a semiconductor with optical gain. A number of devices are discussed based on incorporating a UAP layer in the structure design, such as a polarization-insensitive amplifier, a polarizer, an optically controlled polarization switch, and an optically controlled modal coupler

25 citations

Journal ArticleDOI
TL;DR: In this paper, the shape of the photoluminescence line registered from a side edge of InP wafer is studied as function of the distance from the excitation spot, and the observed red shift in the luminescence maximum is well described by radiation filtering and is consistent with the absorption spectra.
Abstract: The shape of the photoluminescence line registered from a side edge of InP wafer is studied as function of the distance from the excitation spot. The observed red shift in the luminescence maximum is well described by radiation filtering and is consistent with the absorption spectra. Our method provides an independent and accurate determination of the Urbach tails in moderately doped semiconductors.

24 citations

Journal ArticleDOI
TL;DR: In this paper, 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 300 K to 78 K was studied.

18 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
01 May 1983

345 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reported the analysis of the Urbach effect in the absorption spectra of the undoped ZnO thin films and found the phonon energy to be ℏωp=76´±´4´meV.
Abstract: We report the analysis of the Urbach effect in the absorption spectra of the undoped ZnO thin films. The absorption coefficients of the ZnO thin films show the exponential rise, also known as the Urbach tails, just below the free exciton peak. Fitting of the steepness parameter of the Urbach tails yields the phonon energy to be ℏωp=76 ± 4 meV, consistent with ℏωp=72 meV measured from the photoluminescence spectra of ZnO. The temperature dependence of the Urbach energy, the steepness parameter, and the energy gap strongly suggests that the observed Urbach effect is a result of the cumulative effect of impurities, structural disorders, and electron-phonon interaction in the absorption processes.

208 citations

Journal ArticleDOI
08 Apr 2020-Nature
TL;DR: Efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys is demonstrated, enabling electronic and optoelectronic functionalities to be combined on a single chip and in excellent quantitative agreement with ab initio theory.
Abstract: Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si), germanium (Ge) and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. The goal1 of achieving efficient light emission from group-IV materials in silicon technology has been elusive for decades2–6. Here we demonstrate efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. We measure a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observe an emission yield similar to that of direct-bandgap group-III–V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information-processing technologies. A hexagonal (rather than cubic) alloy of silicon and germanium that has a direct (rather than indirect) bandgap emits light efficiently across a range of wavelengths, enabling electronic and optoelectronic functionalities to be combined on a single chip.

208 citations

Journal ArticleDOI
TL;DR: The current understanding of the physics of light emission in state-of-the-art metal-halide perovskite devices is presented and pathways toward reaching device efficiency limits and how the unique properties ofperovskites provide a tremendous opportunity to significantly disrupt both the power generation and lighting industries are outlined.
Abstract: Light emission is a critical property that must be maximized and controlled to reach the performance limits in optoelectronic devices such as photovoltaic solar cells and light-emitting diodes. Halide perovskites are an exciting family of materials for these applications owing to uniquely promising attributes that favor strong luminescence in device structures. Herein, the current understanding of the physics of light emission in state-of-the-art metal-halide perovskite devices is presented. Photon generation and management, and how these can be further exploited in device structures, are discussed. Key processes involved in photoluminescence and electroluminescence in devices as well as recent efforts to reduce nonradiative losses in neat films and interfaces are discussed. Finally, pathways toward reaching device efficiency limits and how the unique properties of perovskites provide a tremendous opportunity to significantly disrupt both the power generation and lighting industries are outlined.

191 citations