Showing papers by "Jan Misiewicz published in 1997"
TL;DR: In this article, the energy-gap-related transitions in GaAs and AlGaAs were observed and the Al content in Al-GaAs was determined using the first derivative of a Gaussian profile of the measured resonances.
Abstract: Results of room-temperature photoreflectance measurements on three GaAs/Al0.33Ga0.67As multiquantum well (MQW) structures with three different widths of wells and on two GaAs/Al0.33Ga0.67As high-electron-mobility transistor (HEMT) structures are presented. Energy-gap-related transitions in GaAs and AlGaAs were observed. The Al content in AlGaAs was determined. MQW transition energies were determined using the first derivative of a Gaussian profile of the measured resonances. In order to identify the transitions in the MQS, the experimentally observed energies were compared with results of the envelope function calculation method for a rectangular quantum well. The Franz–Keldysh oscillation (FKO) model was also used to determine the built-in electric field in various parts of the investigated structures. The values of the electric fields allow us to hypothesise about the origin of these fields. © 1997 John Wiley & Sons, Ltd.
4 citations
TL;DR: In this paper, photoreflectance spectroscopy has been applied to investigate MBE grown GaAs AlGaAs low dimension structures and the electric field in the SL region of the structure has been evaluated.
3 citations
14 Jul 1997
TL;DR: In this article, photoluminescence and reflectivity were studied in magnetic field up to 5T in T equals 4.2 K. In luminescence spectra two lines were observed.
Abstract: Cd0.9Mn0.1Se0.3Te0.7 photoluminescence and reflectivity were studied in magnetic field up to 5T in T equals 4.2 K. In luminescence spectra two lines were observed. Comparing results to previous studies in Cd1-xMnxTe and Cd1-xMnxSe they were identified as the free exciton X and exciton bound to neutral acceptor A0X. Influence of high alloy disorder on bound magnetic polaron effect was considered.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations
TL;DR: In this paper, photoreflectance (PR) spectra were measured at room temperature for energies in the vicinity of the E0 critical point for p-type as well as n-type doped GaAs.
1 citations
13 Jun 1997
TL;DR: In this article, the photoreflectance (PR) spectra at room and liquid nitrogen temperatures of two MBE grown GaAs/AlGaAs structures were measured and the experimental transitions were well described in terms of envelope function model.
Abstract: We have measured the photoreflectance (PR) spectra at room and liquid nitrogen temperatures of two MBE grown GaAs/AlGaAs structures. The first one is HEMT type system with buried 10 periods of 2.5 micrometers GaAs/2.5nm AlGaAs superlattice. Oscillations-like signal associated with this SL have been observed and detailed analyzed. The second investigated structure is the sequence of 10 different quantum wells. Transitions in almost all wells and those associated with above barrier states have been observed. The experimental transitions are well described in terms of envelope function model.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations
13 Jun 1997
TL;DR: In this article, a non-destructive, contactless, room temperature method for photoreflectance spectroscopy of semiconductor layers, interfaces, structures and devices is described.
Abstract: Photoreflectance spectroscopy as the nondestructive, contactless, room temperature method to investigate semiconductor layers, interfaces, structures and devices is presented. Principles of the method are described. Application to the investigations of the III-V and II-VI compounds structures, including quantum wells, heterojunction bipolar transistors, high electron mobility transistors, vertical cavity surface emitting lasers and quantum dots arrays are shown.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: The photoluminescence (PL) spectra of MOCVD-grown GaAs samples have been measured at 10 K, and for the most representative sample, PL spectra were recorded from 10 to 150K.
13 Jun 1997
TL;DR: In this article, the splitting energies derived from theoretical considerations using envelope function model including lattice mismatch-related stress have been compared with values derived from the theoretical considerations derived from envelope function.
Abstract: InGaAs/GaAs quantum wells have been grown in MOCVD system equipped with horizontal Aixtron reactor. Photoreflectance spectra have shown, even at room temperature, sharp heavy and light holes excitonic transitions in quantum wells. The obtained splitting energies have been compared with values derived from theoretical considerations using envelope function model including lattice mismatch-related stress. Heavy and light holes transitions have been identified as excitonic transitions type I and type II, respectively. Photoluminescence measurements have been also done. For quantum wells, transitions between first heavy hole and first electron subbands have been observed. Additionally the temperature dependence of observed transitions have been performed.
13 Jun 1997
TL;DR: The photoluminescence (PL) spectra of MOCVD-grown GaAs samples have been measured at 10K, and for the most representative sample, PL spectra were recorded from 10 to 150K.
Abstract: The photoluminescence (PL) spectra of MOCVD-grown GaAs samples have been measured at 10K, and for the most representative sample, PL spectra were recorded from 10 to 150K. Besides of the well-established transitions, a hitherto unreported peak was seen at 1.454 eV. The identification of a line at 1.408 eV is discussed.