Optical spectroscopy of intact and intermixed GaAs?AIAs superlattice structures. by Philip Scrutton Download PDF EPUB FB2
Reflectance‐difference (RD) studies were performed on variously reconstructed () GaAs and AlAs surfaces. The spectra of the (2×4) and (4×2) reconstructions on () GaAs show prominent features due to electronic transitions between lone‐pair orbitals and dimer states, as previously identified by theoretical calculations.
The spectra of the c(4×4) reconstructions on () GaAs and Cited by: Quantum dot (QD) structure has potential applications in modern highly efficient optoelectronic devices due to their band-tuning. The device dimensions have been miniatured with increased efficiencies by virtue of this discovery.
In this research, we have presented modified analytical and simulation results of InAs/GaAs QD superlattice (QDSL).Cited by: 6. We have investigated the optical properties of gallium arsenide (GaAs) in the photon energy range – eV.
We obtained a refractive index which has a maximum value of at a photon energy of eV; an extinction coefficient which has a maximum value of at a photon energy of eV; the dielectric constant, the real part of the complex dielectric constant has a maximum value of 24 Cited by: M.
Losurdo, G. Bruno, T. Brown, and G. May, "A chemical and Kinetic Study of P-for-As Anion Exchange Reactions in GaAs/GaAsP superlattice structures, EMC conference, Salt Lake city, ( The results demonstrate the considerable potential of SPS for the contactless and nondestructive characterization of pHEMT structures at room temperature.
AB - Using room-temperature surface photovoltage spectroscopy (SPS), we have characterized a GaAlAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (pHEMT) by: 5. found to be in agreement with optical spectroscopy measurements. Our InAs/GaAs QD structures were grown using solid source MBE.
On a heavily doped (1× Optical spectroscopy of intact and intermixed GaAs?AIAs superlattice structures. book n-type () oriented GaAs substrate, nm of GaAs buffer layer was grown followed by 5 periods of InAs QDs.
The QD layers were separated by 50 nm of GaAs. The superlattice was. Electroluminescence and absorption spectra of a ten-layer InAs/GaAs quantum dot (QD) superlattice built in a two-section laser with sections of equal length is experimentally studied at room temperature.
The thickness of the GaAs spacer layer between InAs QD layers, determined by transmission electron microscopy, is ∼6 nm. In contrast to tunnel-coupled QDs, QD superlattices. Δa/a GaAs values calculated from the two (5 1 1) rocking curves from Eq. (1) and corresponding nitrogen mole fractions x calculated either from Eq.
(2) for GaAs 1−x N x or from Eq. (4) for In y Ga 1−y As 1−x N x for the thick-film structures M, M and M are presented in Table In compositions y used in these calculations and obtained from prior calibration on InGaAs.
Optical Spectroscopy bridges a gap by providing a background on optics while focusing on spectroscopic methodologies, tools and instrumentations. The book introduces the most widely used steady-state and time-resolved spectroscopic techniques, makes comparisions between them, and provides the methodology for estimating the most important characteristics of the techniques such as.
Del Sole, P. Chiaradia, in Encyclopedia of Condensed Matter Physics, Conclusions. Optical spectroscopy has become, in the last decades, an important tool for surface analysis, of great sensitivity to structural changes and versatility. The theoretical understanding of the results is becoming more and more satisfactory, thanks to the application of advanced many-body techniques to the.
The purpose of this study was to characterize the optical absorption properties of various semiconductors such as Si, Ge, GaAs, etc, and to investigate how the current knowledge applied in the limit of very high temperatures.
The application of interest was essentially the effect of high temperatures on optical devices, and so the research was. Refractive index n versus photon energy for a high-purity GaAs.(n o ~510 13 cm-3). Solid curve is deduced from two-beam reflectance measurements at K.
Dark circles are obtained from refraction measurements. Light circles are calculated from Kramers-Kronig analysis (Blakemore ). Normal incidence reflectivity versus photon energy. Three GaAs doping superlattice (SL) structures of d n =d p =20, 40, 60 nm thicknesses, grown by low-pressure OMVPE on semi-insulating GaAs substrates were investigated by low-temperature photoluminescence (PL) spectroscopy.
The n-layers were doped with tellurium and p-layers with zinc, n D =n A =1×10 18 cm − response of the SL samples to and 5 keV Ar +. Gnutzmann, K.
Clausecker, Theory of direct optical transitions in an optical indirect semiconductor with a superlattice structure, Appl.
Phys. 3: 9 () Google Scholar 2. Esaki, A bird’s-eve view on the evolution of semiconductor superlattices and quantum wells, IEEE J. Quantum Electron., QE () Google Scholar. In addition to widely used photoluminescence spectroscopy photovoltaic measurement of quantum dot structures can give complementary information about electron and hole transitions.
Structures with self-organized InAs quantum dots in GaAs matrix were grown by the Stranski–Krastanov mechanism using the low pressure metalorganic vapor phase epitaxy technique.
Two types of. Å of GaAs were grown, then the substrate temperature was increased to °C and a Å-thick GaAs layer was grown.
Then, for the ﬁrst structure ~sample A!, this layer was followed by a short period GaAs–AlGaAs superlattice and Å of Al GaAs; a 50 Å GaAs layer was grown on the top for surface protection.
Spatially resolved Raman spectroscopy at room temperature is used to study quantum well intermixing in GaAs:AlAs superlattice structures. Phonon modes are probed from the side facet along the [ Optics and Spectroscopy (Optika i spektroskopiya), founded inpresents original and review papers in various fields of modern optics and spectroscopy in the entire wavelength range from radio waves to X-rays.
Topics covered include problems of theoretical and experimental spectroscopy of atoms, molecules, and condensed state, lasers and the interaction of laser radiation.
The performance and versatility of GaAs/AlGaAs thin-film waveguide technology in combination with quantum cascade lasers for mid-infrared spectroscopy in comparison to conventional FTIR spectroscopy is presented. Infrared radiation is provided by a quantum cascade laser (QCL) spectrometer comprising four tunable QCLs providing a wavelength range of 5–11 μm (−.
A GaAs/GaAlAs-based asymmetric microcavity structure was studied by various optical characterization techniques. The angle-dependent reflectance (R) spectra showed that the cavity mode (CM) superimposed on quantum well excitonic transitions.
The resonance enhancement effect between the excitonic transitions and the CM in the weak-coupling regime was explored using the angle. Reflectance anisotropy spectroscopy (RAS) in combination with reflection high‐energy electron diffraction (RHEED) was used to study in situ the initial steps of molecular beam epitaxial growth of InAs on GaAs().
Due to the large lattice mismatch InAs is known to grow in Stranski–Krastanov mode leading to the formation of quantum dots after the transition from two‐ to three.
Annealing at higher temperature ( °C) of structures with two‐dimensional and three‐dimensional arrays in InAs–GaAs quantum dots (QDs) results in an increase in the size and in a corresponding decrease in the indium composition of the QDs.
The change in the In composition is monitored by the contrast pattern in the plan‐view transmission electron microscopy (TEM) images viewed under. anisotropic surface optical response in GaAs than for Si,6 in part because the main features of the GaAs surface optical anisotropy are near the interband critical points.
This anisot-ropy has been attributed to local-ﬁeld effects,7 the electro-optic effect,8 reconstruction,9 surface dislocations,10 and. A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text.
The GaAs/InAs structures are less intermixed over the temperatures studied, which results in higher mismatch between the individual layers and a higher driving force for roughening and lateral. Low‐temperature optical transmission spectra of several In x Ga 1−x As/GaAs strained multiple quantum wells (MQWs) with different well widths and In mole fractions have been measured.
The excitonic transitions up to 3C‐3H are observed. The notation nc‐mH(L) is used to indicate the transitions related to the nth conduction and mth valence heavy (light) hole subbands. Chapter 6 Ultrafast Optical Absorption Measurments of Electron-Phonon Scattering in GaAs Quantum Wells Altmetric Badge.
Chapter 7 Hot Photoluminescence and Electron-Phonon Interaction in GaAs/AIAs MQW Structures Altmetric Badge. Low-temperature transmittance and room-temperature photoreflectance spectra are presented for a series of In x Ga 1−x As 1−y N y / GaAs (x≈15%) strained-layer multiple quantum well structures grown by molecular-beam epitaxy with a nitrogen concentration ranging from 0% to %.
We have investigated the structure and optical properties of GaAs N / GaAs produced by metalorganic vapor phase epitaxy grown on GaAs surface at – °C. Using cross-sectional transmission electron microscopy and photoluminescence spectroscopy (PL), we show the presence of a 5–6-nm-thick nitrogen-rich interfacial region.
The nitrogen composition near the interface is twice. Spectroscopy is the study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation. Historically, spectroscopy originated as the study of the wavelength dependence of the absorption by gas phase matter of visible light dispersed by a can also consider matter waves and acoustic waves as forms of radiative energy, and.
We studied the photoreflectance (PR) and photoluminescence (PL) spectroscopies of self-assembled InAs quantum dots grown on n +-GaAs () by molecular beam PL spectroscopy of self-assembled Ge quantum dots (Ge-QDs) grown on n +-Si () by metal organic chemical vapor deposition epitaxy was also spectra show the optical transitions from .Optical identification of electronic state levels of an asymmetric InAs/InGaAs/GaAs dot-in-well structure Xiaolong Zhou, 1 Yonghai Chen, 1 and Bo Xu 1 1 Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O.
BoxBeijingPeople's Republic of China.Phase matching in a multilayer AlGaAs waveguide is used to generate mid-IR ( μm) light through difference frequency generation (DFG) between a nm pump and nm signal.