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Wyszukujesz frazę "Harrison, P." wg kryterium: Autor


Wyświetlanie 1-10 z 10
Tytuł:
Quantum Dots as Sources and Detectors οf Mid- and Far-Infrared Radiation: Theoretical Models
Autorzy:
Vukmirović, N.
Indjin, D.
Ikonić, Z.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1791186.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.67.Hc
73.63.Kv
85.60.Gz
85.35.Be
Opis:
We present a review of theoretical methods used to study the electronic structure, optical and transport properties of intraband optoelectronic devices based on self-assembled quantum dots.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 464-467
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intervalley Scattering and the Role of Indirect Band Gap AlAs Barriers: Application to GaAs/AlGaAs Quantum Cascade Lasers
Autorzy:
Mc Tavish, J.
Ikonić, Z.
Indjin, D.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1813212.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
73.63.Hs
Opis:
We report on the results of our simulations of Γ-X scattering in GaAs/AlGaAs heterostructures, discussing the importance of the mole fraction, doping density, and lattice and electron temperature in determining the scattering rates. We consider three systems, a single quantum well (for the investigation of Γ-X scattering), a double quantum well (to compare the Γ-X-G and Γ-Γ scattering rates), and an example of a GaAs/AlGaAs mid-infrared quantum cascade laser. Our simulations suggest that Γ-X scattering can be significant at room temperature but falls off rapidly at lower temperatures. One important factor determining the scattering rate is found to be the energy difference between the Γ- and X-states.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 891-902
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge Carrier Transport in Quantum Cascade Lasers in Strong Magnetic Field
Autorzy:
Radovanović, J.
Milanović, V.
Indjin, D.
Ikonić, Z.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1505456.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.-d
73.21.Fg
Opis:
We have developed a comprehensive rate equations based model for calculating the optical gain in the active region of a quantum cascade laser in magnetic field perpendicular to the structure layers, which takes into account all the relevant scattering channels. The model is applied to gain-optimized quantum cascade laser active region, obtained by a systematic optimization procedure based on the use of genetic algorithm, which we have previously set up for designing novel structures and improving performance of existing ones. It has proven to be very efficient in generating optimal structures which emit radiation at specified wavelengths corresponding to absorption fingerprints of particular harmful pollutants found in the atmosphere. We also illustrate another interesting prospective application of quantum cascade laser-type structures: the design of metamaterials with tunable complex permittivity, based on amplification via intersubband transitions. In this case, the role of the magnetic field is to assist the attainment of sufficient optical gain (population inversion), necessary to effectively manipulate the permittivity and fulfill the conditions for negative refraction (left-handedness).
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 99-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Precession of Quasi-Bound States in Heterostructures with Spin-Orbit Interaction
Autorzy:
Isić, G.
Indjin, D.
Ikonić, Z.
Milanović, V.
Radovanović, J.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/1791209.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ej
73.20.At
73.21.Fg
Opis:
We use a finite-difference model that is capable of describing the single state spin dynamics in a double-barrier AlGaAs heterostructure. The use of Green's functions enables a description of the double-barrier structure by a finite matrix while the interaction with contacts is described by appropriate self-energies. To account for interface roughness scattering, a self-energy $Σp_{IR}$(E, k) is derived within the random phase approximation. The dominant part is due to in-plane momentum relaxation while a smaller part describing spin-flip scattering is neglected. The former only decreases the state lifetime while the latter can also affect the spin precession frequency.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 513-515
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiative Recombination Spectra of Heavily p-Type δ-Doped GaAs/AlAs MQWs
Autorzy:
Kundrotas, J.
Čerškus, A.
Valušis, G.
Lachab, M.
Khanna, S.
Harrison, P.
Linfield, E.
Powiązania:
https://bibliotekanauki.pl/articles/1813382.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.-m
78.67.De
71.30.+h
Opis:
We present a study of the photoluminescence properties of heavily Be δ-doped GaAs/AlAs multiple quantum wells measured at room and liquid nitrogen temperatures. Possible mechanisms for photocarriers recombination are discussed, with a particular focus on the peculiarities of the excitonic and free carriers-acceptors photoluminescence emissions occurring below and above the Mott metal-insulator transition. Moreover, based on a simple theoretical model, it is found that the critical impurities concentration to observe the Mott transition in the multiple quantum wells samples exhibiting 15 nm wells width and 5 nm thick barrier layers is ≈3×$10^{12} cm^{-2}$.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 963-966
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study of Optical Transitions in Be-Doped GaAs/AlAs Multiple Quantum Wells
Autorzy:
Kundrotas, J.
Čerškus, A.
Ašmontas, S.
Valušis, G.
Sherliker, B.
Halsall, M.
Harrison, P.
Steer, M.
Powiązania:
https://bibliotekanauki.pl/articles/1178273.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.-y
78.55.-m
Opis:
We present a photoluminescence study of optical transitions in Be acceptor-doped GaAs/AlAs multiple quantum wells at room and liquid nitrogen temperatures. We investigate excitonic spectra and reveal acceptor-impurity induced effects in multiple quantum wells having different width.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 245-249
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carrier Dynamics in Quantum Cascade Lasers
Autorzy:
Harrison, P.
Indjin, D.
Jovanović, V. D.
Mirčetić, A.
Ikonić, Z.
Kelsall, R. W.
McTavish, J.
Savić, I.
Vukmirović, N.
Milanović, V.
Powiązania:
https://bibliotekanauki.pl/articles/2041634.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.60.-v
Opis:
A fully quantum-mechanical model for carrier scattering transport in semiconductor intersubband devices was applied to modelling of carrier dynamics in quantum cascade lasers. The standard model uses the envelope function and effective mass approximations to solve electron band structure under an applied bias. The k·p model has been employed in p-type systems where the more complex band structure requires it. The resulting wave functions are then used to evaluate all relevant carrier-phonon, carrier-carrier and alloy scattering rates from each quantised state to all others within the same and the neighbouring period. This piece of information is then used to construct a rate equation for the equilibrium carrier density in each subband and this set of coupled rate equations are solved self-consistently to obtain the carrier density in each eigenstate. The latter is a fundamental description of the device and can be used to calculate the current density and gain as a function of the applied bias and temperature, which in turn yields the threshold current and expected temperature dependence of the device characteristics. A recent extension which includes a further iteration of an energy balance equation also yields the electron (or hole) temperature over the subbands. This paper will review the method and describe its application to mid-infrared and terahertz, GaAs, GaN, and SiGe cascade laser designs.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 75-81
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Terahertz Characterization of Be-Doped GaAs/AlAs Multiple Quantum Wells
Autorzy:
Čechavičius, B.
Kavaliauskas, J.
Krivaitė, G.
Seliuta, D.
Širmulis, E.
Devenson, J.
Valušis, G.
Sherliker, B.
Halsall, M.
Steer, M.
Harrison, P.
Powiązania:
https://bibliotekanauki.pl/articles/2041764.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
85.30.De
Opis:
We report on optical, photoreflectance and surface photovoltage, as well as terahertz photocurrent investigation of Be-doped GaAs/AlAs multiple quantum wells at room and liquid helium temperatures, respectively. From the Franz-Keldysh oscillations observed in photoreflectance spectra we determine built-in electric fields within the structure. Interband transition energies calculated by the transfer matrix method are in qualitative agreement with experimentally determined values for the samples having various, from 2×10$\text{}^{10}$ up to 2.5×10$\text{}^{12}$ cm$\text{}^{-2}$, Be doping densities. The photocurrent observed in the range of 5.4-7.3 THz we associate with photoionization of Be-acceptor states.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 328-332
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Terahertz Detection with δ-Doped GaAs/AlAs Multiple Quantum Wells
Autorzy:
Seliuta, D.
Čechavičius, B.
Kavaliauskas, J.
Krivaitė, G.
Grigelionis, I.
Balakauskas, S.
Valušis, G.
Sherliker, B.
Halsall, M.
Lachab, M.
Khanna, S.
Harrison, P.
Linfield, E.
Powiązania:
https://bibliotekanauki.pl/articles/1813214.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
85.30.De
Opis:
The authors demonstrate selective detection of terahertz radiation employing berylliumδ-doped GaAs/AlAs multiple quantum wells. The sensitivity up to 1 V/W within 4.2-7.3 THz range at liquid helium temperatures is reached. The Franz-Keldysh oscillations observed in photo- and electroreflectance spectra allowed one to estimate built-in electric fields in the structures studied. It was found that the electric field strength in the cap layer region could vary from 10 kV/cm up to 26 kV/cm, depending on the structure design and temperature.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 909-912
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Normal Incidence Mid-Infrared Photocurrent in AlGaN/GaN Quantum Well Infrared Photodetectors
Autorzy:
Sherliker, B.
Halsall, M. P.
Harrison, P.
Jovanović, V. D.
Indjin, D.
Ikonić, Z.
Parbrook, P. J.
Whitehead, M. A.
Wang, T.
Buckle, P. D.
Phillips, J.
Carder, D.
Powiązania:
https://bibliotekanauki.pl/articles/2041680.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
Opis:
We report the growth and characterization of AlGaN/GaN multiple quantum well structures designed to have intersubband transitions in the mid-infrared region of the spectrum. The samples were nominally undoped but were found to contain a high electron population in the wells induced by the local polarization fields. The sample was characterized by the use of the Raman spectroscopy and photocurrent spectroscopy. The Raman spectroscopy shows electronic Raman scattering from intersubband transitions in the AlGaN/GaN quantum wells. The e$\text{}_{1}$-e$\text{}_{2}$ and e$\text{}_{1}$-e$\text{}_{3}$ transitions of the confined 2d electron population in the wells can clearly be observed. A sample designed to absorb at 4μm was fabricated into mesa structures and the vertical photocurrent measured under normal incidence illumination from the free-electron laser FELIX. A wavelength and bias dependent photocurrent was observed in the mid-IR region of spectrum. The peak responsivity was of the order of 50μA/W at 4 K, the photocurrent still being measurable at room temperature.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 174-178
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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