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Author | Elvira, D.; Michon, A.; Fain, B.; Patriarche, G.; Beaudoin, G.; Robert-Philip, I.; Vachtomin, Y.; Divochiy, A. V.; Smirnov, K. V.; Gol’tsman, G. N.; Sagnes, I.; Beveratos, A. | ||||
Title | Time-resolved spectroscopy of InAsP/InP(001) quantum dots emitting near 2 μm | Type | Journal Article | ||
Year | 2010 | Publication | Appl. Phys. Lett. | Abbreviated Journal | Appl. Phys. Lett. |
Volume | 97 | Issue | 13 | Pages | 131907 (1 to 3) |
Keywords | SSPD, SNSPD, InAsP/InP quantum dots | ||||
Abstract ![]() |
By using superconducting single photon detectors, we perform time-resolved characterization of a small ensemble of InAsP/InP quantum dots grown by metal organic vapor phase epitaxy, emitting at wavelengths between 1.6 and 2.2 μm. We demonstrate that alloying phosphorus with InAs allows to shift the emission wavelength toward higher wavelengths, while keeping the high optical quality of these quantum dots at room temperature, with no decrease in their radiative lifetime. This work was partially supported by Russian Ministry of Science and Education: Federal State Program “Scientific and Educational Cadres of Innovative” state Contract Nos. 02.740.0228, 14.740.11.0343, 14.740.11.0269, and P931, and RFBR Project No. 09-02-12364. | ||||
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ISSN | 0003-6951 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1238 | |||
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Author | Mooij, J. E.; Dekker, P. | ||||
Title | Static properties of two- and three-dimensional superconducting constrictions | Type | Journal Article | ||
Year | 1978 | Publication | J. Low Temp. Phys. | Abbreviated Journal | J. Low Temp. Phys. |
Volume | 33 | Issue | 5/6 | Pages | 551-576 |
Keywords | superconducting microbridges, superconducting strip, coherence length | ||||
Abstract ![]() |
Calculations have been performed on superconducting constrictions with hyperbolic geometry. Stationary Ginzburg-Landau equations are used, neglecting magneticfields. Emphasis is placed on the difference between two-and three -dimensional constrictions, which is related to the difference between uniform-thickness (UT) and variable-thickness (VT) superconducting microbridges. The width of the constriction w, normalized to the coherence length ξ is indicated by the parameter A (â‰<192> w/2ξ). It is found that small (A < 0.1), three-dimensional constrictions and VT bridges have a sinusoidal current-phase relation, linear temperature dependence of the critical current I c, and an I cR product (Ris the normal state resistance) equal to the Ambegaokar-Baratoff expression for Josephson junctions near T c. Two-dimensional constrictions behave as if they consist of an inner core with junction properties, in series with the films on both sides. The core consists of the region within a coherence length from the center of the structure. This size is temperature dependent. The core shows a sinusoidal current-phase relation and IcR according to Ambegaokar and Baratoff. For the whole constriction neither the phase difference nor R is finite. Two-dimensional constrictions have linear temperature dependence only when they are extremely narrow (A < 0.001). In two-dimensionalbridges the order parameter is depressed cover a distance of approximately the coherence length; in small three-dimensional constrictions this distance is approximately equal to the width. In narrow constrictions (and short microbridges) the current is not homogeneously distributedover the cross section. The effect has been investigated that occurs when in three-dimensional constrictions the width w is not much larger than l 0, the electron mean free path in the basic material. To this purpose a Ginzburg-Landau equation is derived from the Zaitsev boundary conditions which is valid for continuously changing material parameters. The critical current is decreased, but the IcR product remains constant.The results of the calculations are compared with experimental results for superconducting microbridges. | ||||
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Notes | Recommended by Klapwijk | Approved | no | ||
Call Number | Serial | 926 | |||
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Author | Pyatkov, Felix; Khasminskaya, Svetlana; Fütterling, Valentin; Fechner, Randy; Słowik, Karolina; Ferrari, Simone; Kahl1, Oliver; Kovalyuk, Vadim; Rath, Patrik; Vetter, Andreas; Flavel, Benjamin S.; Hennrich, Frank; Kappes, Manfred M.; Gol’tsman, Gregory N.; Korneev, Alexander; Rockstuhl, Carsten; Krupke, Ralph; Pernice, Wolfram H. P. | ||||
Title | Carbon nanotubes as exceptional electrically driven on-chip light sources | Type | Miscellaneous | ||
Year | 2016 | Publication | 2Physics | Abbreviated Journal | 2Physics |
Volume | Issue | Pages | |||
Keywords | carbon nanotubes, CNT | ||||
Abstract ![]() |
Carbon nanotubes (CNTs) belong to the most exciting objects of the nanoworld. Typically, around 1 nm in diameter and several microns long, these cylindrically shaped carbon-based structures exhibit a number of exceptional mechanical, electrical and optical characteristics [1]. In particular, they are promising ultra-small light sources for the next generation of optoelectronic devices, where electrical components are interconnected with photonic circuits. Few years ago, we demonstrated that electically driven CNTs can serve as waveguide-integrated light sources [2]. Progress in the field of nanotube sorting, dielectrophoretical site-selective deposition and efficient light coupling into underlying substrate has made CNTs suitable for wafer-scale fabrication of active hybrid nanophotonic devices [2,3]. Recently we presented a nanotube-based waveguide integrated light emitters with tailored, exceptionally narrow emission-linewidths and short response times [4]. This allows conversion of electrical signals into well-defined optical signals directly within an optical waveguide, as required for future on-chip optical communication. Schematics and realization of this device is shown in Figure 1. The devices were manufactured by etching a photonic crystal waveguide into a dielectric layer following electron beam lithography. Photonic crystals are nanostructures that are also used by butterflies to give the impression of color on their wings. The same principle has been used in this study to select the color of light emitted by the CNT. The precise dimensions of the structure were numerically simulated to tailor the properties of the final device. Metallic contacts in the vicinity to the waveguide were fabricated to provide electrical access to CNT emitters. Finally, CNTs, sorted by structural and electronic properties, were deposited from a solution across the waveguide using dielectrophoresis, which is an electric-field-assisted deposition technique. |
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ISSN | 2372-1782 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | Approved | no | |||
Call Number | Serial | 1219 | |||
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Author | Pyatkov, F.; Khasminskaya, S.; Kovalyuk, V.; Hennrich, F.; Kappes, M. M.; Goltsman, G. N.; Pernice, W. H. P.; Krupke, R. | ||||
Title | Sub-nanosecond light-pulse generation with waveguide-coupled carbon nanotube transducers | Type | Journal Article | ||
Year | 2017 | Publication | Beilstein J. Nanotechnol. | Abbreviated Journal | Beilstein J. Nanotechnol. |
Volume | 8 | Issue | Pages | 38-44 | |
Keywords | carbon nanotubes; CNT; infrared; integrated optics devices; nanomaterials | ||||
Abstract ![]() |
Carbon nanotubes (CNTs) have recently been integrated into optical waveguides and operated as electrically-driven light emitters under constant electrical bias. Such devices are of interest for the conversion of fast electrical signals into optical ones within a nanophotonic circuit. Here, we demonstrate that waveguide-integrated single-walled CNTs are promising high-speed transducers for light-pulse generation in the gigahertz range. Using a scalable fabrication approach we realize hybrid CNT-based nanophotonic devices, which generate optical pulse trains in the range from 200 kHz to 2 GHz with decay times below 80 ps. Our results illustrate the potential of CNTs for hybrid optoelectronic systems and nanoscale on-chip light sources. | ||||
Address | Department of Materials and Earth Sciences, Technische Universitat Darmstadt, Darmstadt 64287, Germany | ||||
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ISSN | 2190-4286 | ISBN | Medium | ||
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Notes | PMID:28144563; PMCID:PMC5238692 | Approved | no | ||
Call Number | RPLAB @ kovalyuk @ | Serial | 1109 | ||
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Author | Gershenzon, E. M.; Gol'tsman, G. N.; Ptitsina, N. G.; Riger, E. R. | ||||
Title | Effect of electron-electron collisions on the trapping of free carriers by shallow impurity centers in germanium | Type | Journal Article | ||
Year | 1986 | Publication | Sov. Phys. JETP | Abbreviated Journal | Sov. Phys. JETP |
Volume | 64 | Issue | 4 | Pages | 889-897 |
Keywords | Ge, trapping of free carriers | ||||
Abstract ![]() |
Cascade Auger recombination of free carriers on shallow impurities in Ge is investigated under quasi-equilibrium conditions (T= 2-12 K) and in impurity breakdown. The Auger capture cross sections are found to be a,= 5. 10-l9 T-'n cm2 for donors and uip= 7- T-5p cm2 for acceptors. It is shown that in an isotropic semiconductor (p-Ge) ui is well described by the cascade-capture theory that takes into account only electron-electron collisions. In an anisotropic semiconductor ui is considerably larger (n-Ge, strongly uniaxially compressedp-Ge). Under impurity breakdown conditions the electron-electron collisions determine the lifetimes of the free carriers only in samples with appreciable density of the compensating impurity (Nk loi3 cmP3). | ||||
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Notes | Approved | no | |||
Call Number | Serial | 1707 | |||
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