Observation of phonon modes in epitaxial PbTe films grown by molecular beam epitaxy

2007 ◽  
Vol 101 (10) ◽  
pp. 103505 ◽  
Author(s):  
Huizhen Wu ◽  
Chunfang Cao ◽  
Jianxiao Si ◽  
Tianning Xu ◽  
Hanjie Zhang ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Phonon Modes

Optical phonon modes in InGaN/GaN dot-in-a-wire heterostructures grown by molecular beam epitaxy

2013 ◽  
Vol 102 (12) ◽  
pp. 121901 ◽  
Author(s):  
J. Titus ◽  
H. P. T. Nguyen ◽  
Z. Mi ◽  
A. G. U. Perera
Keyword(s):  
Molecular Beam Epitaxy ◽  
Optical Phonon ◽  
Molecular Beam ◽  
Phonon Modes

Excitation Wavelength Dependent Raman Scattering in Low and Highly Degenerate InN Films

2004 ◽  
Vol 831 ◽  
Author(s):  
V.M. Naik ◽  
H. Dai ◽  
R. Naik ◽  
D.B. Haddad ◽  
J.S. Thakur ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Raman Scattering ◽  
Excitation Energy ◽  
Raman Spectra ◽  
Molecular Beam ◽  
Optical Bandgap ◽  
Structural Defects ◽  
Excitation Wavelength ◽  
Phonon Modes ◽  
Energy Mode

ABSTRACTThe Raman spectra of low and highly degenerate InN films grown by conventional Molecular Beam Epitaxy (MBE) and Plasma Source Molecular Beam Epitaxy (PSMBE) have been studied using visible (514.5 nm) and near infrared (785 nm) excitation wavelengths. The MBE grown InN films have a low electron carrier concentration, ne < 2.0 × 1019 cm−3, exhibiting an optical bandgap absorption edge of 0.6 to 0.7 eV. On the other hand PSMBE grown InN samples are highly degenerate with ne > 3 × 1020 cm−3 with an observed optical bandgap ranging from 1.5 to 1.9 eV. Raman spectra of low degenerate InN films show sharp E2 and A1(LO) modes whereas spectra of highly degenerate InN films show rather broad features indicating the presence of a large number of structural defects. In the latter samples a resonance enhanced Raman scattering is observed especially with 785 nm excitation energy, where the excitation energy matches the optical energy bandgap. Another interesting observation is that the expected coupled plasmon LO-phonon modes are not detected in these films, rather a phonon mode is observed at the location of the unscreened A1(LO) mode. The observation of unscreened LO-phonon, and the absence of coupled plasmon LO-phonon modes have been attributed to Landau damping of the higher energy mode and coupling of the lower energy mode with the electron-hole pair excitations leading to the emergence of a mode very close to the A1(LO) mode.

scholarly journals Bandgap measurements and the peculiar splitting of E2H phonon modes of InxAl1-xN nanowires grown by plasma assisted molecular beam epitaxy

2016 ◽  
Vol 120 (4) ◽  
pp. 045701 ◽  
Author(s):  
Malleswararao Tangi ◽  
Pawan Mishra ◽  
Bilal Janjua ◽  
Tien Khee Ng ◽  
Dalaver H. Anjum ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Phonon Modes

EQUALLY STRAINED Si/SiGe SUPERLATTICES ON Si SUBSTRATES

1985 ◽  
Vol 56 ◽  
Author(s):  
E. KASPER ◽  
H.-J. HERZOG ◽  
H.DAEMBKES-a1 ◽  
G. ABSTREITER
Keyword(s):  
Molecular Beam Epitaxy ◽  
Room Temperature ◽  
Molecular Beam ◽  
Electron Gas ◽  
Phonon Modes ◽  
Strained Si ◽  
Si Substrates ◽  
Device Applications ◽  
Strained Layer Superlattices ◽  
Material Concept

AbstractGrowth of Si/SiGe superlattices on Si substrates by molecular beam epitaxy (MBE) is described. Strain symmetrization in the superlattice is achieved with an incommensurate SiGe buffer layer. The concept of strainsymmetrization is explained and properties of buffer and strained layer superlattices are investigated. A twodimensional electron gas with enhanced room temperature mobility and folded phonon modes within the reduced onedimensional Brillouin zone are observed. An n-channel Si/SiGe MODFET demonstrates the device applications of this material concept.

Defects in Heavily-Doped MBE GaAs

1982 ◽  
Vol 40 ◽  
pp. 442-445
Author(s):  
C.B. Carter ◽  
D.M. DeSimone ◽  
T. Griem ◽  
C.E.C. Wood
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Heavily Doped

Molecular-beam epitaxy (MBE) is potentially an extremely valuable tool for growing III-V compounds. The value of the technique results partly from the ease with which controlled layers of precisely determined composition can be grown, and partly from the ability that it provides for growing accurately doped layers.

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

Near-Surface Aggregation of Sn In Heavily Sn-Doped GaAs Films Grown By Molecular Beam Epitaxy

1985 ◽  
Vol 43 ◽  
pp. 368-369
Author(s):  
S. H. Chen
Keyword(s):  
Molecular Beam Epitaxy ◽  
Cross Section ◽  
Electron Spectroscopy ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Secondary Ion Mass Spectrometry ◽  
Specimen Preparation ◽  
Near Surface ◽  
Gaas Films ◽  
Secondary Ion

Sn has been used extensively as an n-type dopant in GaAs grown by molecular-beam epitaxy (MBE). The surface accumulation of Sn during the growth of Sn-doped GaAs has been observed by several investigators. It is still not clear whether the accumulation of Sn is a kinetically hindered process, as proposed first by Wood and Joyce, or surface segregation due to thermodynamic factors. The proposed donor-incorporation mechanisms were based on experimental results from such techniques as secondary ion mass spectrometry, Auger electron spectroscopy, and C-V measurements. In the present study, electron microscopy was used in combination with cross-section specimen preparation. The information on the morphology and microstructure of the surface accumulation can be obtained in a fine scale and may confirm several suggestions from indirect experimental evidence in the previous studies.

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