Showing papers by "Jan Misiewicz published in 2000"
TL;DR: In this article, photoreflectance (PR) spectroscopy has been applied to the investigation of Si δ-doped GaAs, Al 0.35 Ga 0.65 As and AlAs layers grown by metal-organic vapor phase epitaxy (MOVPE) on GaAs substrates.
24 citations
TL;DR: In this article, the influence of nitrogen on the electronic structure and on the optical properties of the quantum well has been analyzed, and the observed optical transitions have been identified on the base of the results of the envelope function calculation including strain effects.
10 citations
Journal Article•
9 citations
TL;DR: In this paper, the authors investigated the optical transitions in strained In 0045 Ga 0955 As/GaAs multiple quantum wells, where the structures were grown by molecular beam epitaxy for different GaAs barrier thickness (1, 3, 5 and 9 monolayers) and for different numbers of wells (3 and 4).
7 citations
TL;DR: In this paper, the absorption and emission spectra of CdF 2 : 0.5% SmF 3 crystal were investigated in the temperature range 6-300 K and it has been demonstrated that apart from the narrow f-f transitions of the Sm 3+ ion there appears a broad band emission whose nature is briefly discussed.
5 citations
01 Jan 2000
TL;DR: In this paper, it was shown that when the barrier is so narrow that there is considerable overlap of wave functions in the two quantum wells, the single quantum well electronic one-particle states split into symmetric and antisymmetric states with different energy levels.
Abstract: Electronically symmetric coupled double quantum wells are structures where two quantum wells are separated by a thin barrier layer. Both experiment and theory show that when the barrier is so narrow that there is considerable overlap of wave functions in the two wells, the single quantum well electronic one-particle states split into symmetric and antisymmetric states with different energy levels. The splitting of energy levels is very sensitive to barrier width and barrier height and increases with decreasing barrier width and with decreasing barrier height.
2 citations
TL;DR: In this paper, room temperature photoreflectance spectroscopy (PR) was used to investigate MBE grown AlxGa1−xAs/GaAs doped structures.
Abstract: Room temperature photoreflectance spectroscopy (PR) was used to investigate MBE grown AlxGa1−xAs/GaAs doped structures. For some structures photoreflectance spectra exhibit superposition of Franz – Keldysh oscillations. Using the 632.8 nm line from an He – Ne laser and the 457.9 nm line from an Ar+ laser alternately as the pump light, the Franz – Keldysh oscillations from different interfaces were separated. From the period of the oscillations, the built-in electric field at two interfaces was determined. The dependence of the direct band-gap energy on the Al content was also investigated. To obtain the direct band gap energy, the measured photoreflectance spectra were analysed using Aspnes lineshape procedure. The determined EAlGaAs dependence on x for doped AlxGa1−xAs layers was compared with previous data. Copyright © 2000 John Wiley & Sons, Ltd.
2 citations
TL;DR: In this article, the authors present results on well-resolved measurements and theoretical treatment of reflectance spectra in the free-exciton region of MOVPE-grown ZnSe/GaAs epilayers under additional above band-gap illumination.
1 citations
TL;DR: In this paper, the radiative recombination in the be-doped single heterojunction Al 0.5 Ga 0.1 As/GaAs, so-called H-band, has been studied by photoluminescence (PL) and photolumininescence excitation (PLE) spectroscopy.
1 citations
TL;DR: In this paper, photoluminescence (PL) spectra of modulation doped p-type Al1−xGaxAs/GaAs heterostructures were studied at GaAs band gap region under the magnetic field up to 8 T in Faraday configuration.
01 Jan 2000
TL;DR: In this paper, the origin of the H-band emission was investigated and it was shown that two-dimensional (2D) carriers tunnel from the triangular well at the interface and recombine with free carriers (3D) in the flat band region.
Abstract: Radiative recombination processes associated with the A1xGa1-xAs/GaAs heterojunction interface have been intensively studied recently. Yuan et al. [1] first observed the PL line on the low energy side of the GaAs exciton, the so-called the H-band, from a single heterojunction. They attributed the H-band emission to two-dimensional (2D) carriers that tunnel from the triangular well at the interface and recombine with free carriers (3D) in the flat band region. Most later papers concerned n-type samples with 2D electrons recombining with free holes [2-4]. Some papers [2,3,5] agreed with Yuan’s explanation of the H-band peak, but other authors concluded that recombining electrons and holes are bound by Coulomb interaction [4, 6]. In this paper we present results of experimental and theoretical studies which shed new light on the origin of the H-band emission phenomenon.
TL;DR: It is concluded that the most suitable optimization methods for nonlocal empirical pseudopotential method (NEPM) is adaptive simulated annealing (ASA), which allows for linear increase of the speed of calculations with the number of processors.
Abstract: We propose a parallel method for calculating the energy band structure. Our method can be easily implemented and does not require high speed of communication between the processors. In practical application our method allows for linear increase of the speed of calculations with the number of processors. We also analyse the optimization algorithms for energy band structure. We conclude that the most suitable optimization methods for nonlocal empirical pseudopotential method (NEPM) is adaptive simulated annealing (ASA).