Computer Investigations of Features of RHEED Oscillations for GaAs and for Ge

2013 ◽  
Vol 203-204 ◽  
pp. 347-350
Author(s):  
Zbigniew Mitura
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Incident Beam ◽  
Diffraction Theory ◽  
Oscillation Phase ◽  
Dynamical Diffraction ◽  
Wide Range ◽  
Glancing Angle ◽  
Scattering Potential ◽  
Experimental Findings

During molecular beam epitaxy regular oscillations of the intensity of the specularly reflected beam often occur. The phenomenon of such oscillations is still theoretically explained only partially. For example it is not clear why usually the oscillation phase depends strongly on the glancing angle of the incident beam. However, quite recently interesting results were shown in the literature on the features of RHEED oscillations observed during the growth of Ge layers. The phase of oscillations practically stays constant for a wide range of angles. So in this paper, we show results of RHEED dynamical calculations for Ge. They are presented together with results of calculations for GaAs to make analysis executed more complete. It is concluded that experimental findings for Ge for off-symmetry azimuths can be explained using dynamical diffraction theory employing the proportional model (for which the scattering potential of the layer is determined as the potential of the completed layer multiplied by the coverage).

Algorithms for determining the phase of RHEED oscillations

2015 ◽  
Vol 48 (6) ◽  
pp. 1927-1934 ◽  
Author(s):  
Zbigniew Mitura ◽  
Sergei L. Dudarev
Keyword(s):  
Experimental Data ◽  
Direct Method ◽  
Incident Beam ◽  
Diffraction Theory ◽  
High Energy ◽  
Angle Of Incidence ◽  
High Energy Electron ◽  
Dynamical Diffraction ◽  
Glancing Angle ◽  
Low Symmetry

Oscillations of reflection high-energy electron diffraction (RHEED) intensities are computed using dynamical diffraction theory. The phase of the oscillations is determined using two different approaches. In the first, direct, approach, the phase is determined by identifying the time needed to reach the second oscillation minimum. In the second approach, the phase is found using harmonic analysis. The two approaches are tested by applying them to oscillations simulated using dynamical diffraction theory. The phase of RHEED oscillations observed experimentally is also analysed. Experimental data on the variation of the phase as a function of the glancing angle of incidence, derived using the direct method, are compared with the values computed using both the direct and harmonic methods. For incident-beam azimuths corresponding to low-symmetry directions, both approaches produce similar results.

Influence of near-surface graded-gap layers on electrical characteristics of MIS-structures based on MBE grown HgCdTe

2010 ◽  
Vol 18 (3) ◽  
Author(s):  
A.V. Voitsekhovskii ◽  
S.N. Nesmelov ◽  
S.M. Dzyadukh ◽  
V.S. Varavin ◽  
S.A. Dvoretskii ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Space Charge Region ◽  
Molecular Beam ◽  
Differential Resistance ◽  
Anodic Oxide ◽  
Electrical Characteristics ◽  
Near Surface ◽  
Wide Range ◽  
Minority Carriers ◽  
Mis Structures

AbstractThe paper examines influence of near-surface graded-gap layers on electrical characteristics of MIS-structures fabricated on heteroepitaxial Hg1−xCdxTe films grown by molecular beam epitaxy (MBE). Two types of insulators, i.e., two-layer SiO2/Si3N4 and anodic oxide films were used. As it is seen from the depth and width of the valley on the C-V characteristics, the capacitance is found to vary in a wide range, in contrast to the structures without graded-gap layers. It is shown that the graded-gap layer under MIS-structures with x = 0.22 effectively reduces the tunnelling generation via deep levels and increases a lifetime of minority carriers in the space charge region and its differential resistance. The properties of the HgCdTe-insulator interfaces are studied.

Improved optical qualities of tilted T-shaped quantum wires fabricated by glancing-angle molecular beam epitaxy

1997 ◽  
Vol 175-176 ◽  
pp. 809-813 ◽  
Author(s):  
N. Tomita ◽  
T. Kishi ◽  
K. Takekawa ◽  
K. Fujita ◽  
T. Watanabe ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Quantum Wires ◽  
Glancing Angle

On the substrate temperature dependence of the properties of In0.52Al0.48As/InP structures grown by molecular beam epitaxy

1996 ◽  
Vol 11 (9) ◽  
pp. 2158-2162 ◽  
Author(s):  
S.F. Yoon ◽  
Y. B. Miao ◽  
K. Radhakrishnan ◽  
S. Swaminathan
Keyword(s):  
Molecular Beam Epitaxy ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
Lattice Mismatch ◽  
Strong Dependence ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Wide Range ◽  
Energy Peak ◽  
Substrate Temperatures

Growth of In0.52Al0.48As epilayers on InP(100) substrates by molecular beam epitaxy at a wide range of substrate temperatures (470–550 °C) is carried out. Low temperature photoluminescence (PL) and double-axis x-ray diffraction (XRD) measurements showed a strong dependence of the PL and XRD linewidths and lattice mismatch on the substrate temperature. Minimum PL and XRD linewidths and lattice mismatch were found to occur at substrate temperatures of between ≈500 and 520 °C under the beam fluxes used in this study. The XRD intensity ratios (Iepi/Isub) were generally higher within the same substrate temperature range at which the lattice mismatch was the lowest. XRD rocking curves of samples grown at low temperatures showed the main epilayer peak to be composed of smaller discrete peaks, suggesting the presence of regions with different lattice constants in the material. PL spectra taken at increasing temperatures showed the quenching of the main emission peak followed by the evolution of a distinct lower energy peak which is possibly associated with deep lying centers.

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