Far Infrared Spectroscopy of In0.53Ga0.47As Quantum Wells on InP(100)

2002 ◽  
Vol 744 ◽  
Author(s):  
N. L. Rowell ◽  
D. J. Lockwood ◽  
P. J. Poole ◽  
G. Yu
Keyword(s):  
Quantum Wells ◽  
Far Infrared ◽  
Interface Layer ◽  
Scanning Tunneling ◽  
Multiple Quantum ◽  
Chemical Beam Epitaxy ◽  
Phonon Confinement ◽  
Phonon Modes ◽  
Cross Sectional ◽  
Interface Layers

ABSTRACTPolarized far infrared reflectance was measured at oblique incidence for In0.53Ga0.47As / InP multiple quantum wells grown by chemical beam epitaxy on InP(100) wafers. Both the well thickness (0.25 - 20 nm) and number of periods (10 - 40) were varied. The reflectance spectra contained sharp Berreman modes at the frequencies of the transverse (TO) and longitudinal (LO) optical phonons. The contributions of the individual phonons were resolved with the model fits. Interface layer phonon modes were observed with intensity increasing with number of wells. The interface layers were 0.6 nm thick and of different composition to adjoining wells consistent with cross-sectional scanning tunneling microscope results on the same samples. The variation due to phonon confinement of the InAs- and GaAs-like LO and TO phonon frequencies was obtained.

Scanning Tunneling Microscope-Induced Luminescence Studies of Defects in GaN Layers and Heterostructures

1999 ◽  
Vol 588 ◽  
Author(s):  
S. Evoy ◽  
C. K. Harnett ◽  
S. Keller ◽  
U. K. Mishra ◽  
S. P. DenBaars ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Scanning Tunneling Microscope ◽  
Multiple Quantum Well ◽  
Scanning Tunneling ◽  
Nanometer Scale ◽  
Multiple Quantum ◽  
Proof Of Concept ◽  
Cross Sectional ◽  
Tunneling Microscope ◽  
Nm Range

AbstractWe present the scanning tunneling microscope-induced luminescence (STL) imaging of defects in optoelectronic materials. Resolution is first discussed using cross-sectional images of InGaAs/GaAs quantum dots. Proof of concept is then provided through the nanometer-scale imaging of GaN layers and quantum wells. The expected λ=356±25 nm range dominates the low temperature STL of GaN. Mapping of luminescence shows circular non-emitting areas around threading dislocations. Extent of dark areas suggests a hole diffusion length of Ld=30–55 nm, in agreement with reported values. The expected λ=450±35 nm range dominates the STL from a buried InGaN/GaN multiple quantum well. Imaging reveals 30–100 nm wide smooth fluctuations of luminescence.

FAR INFRARED MAGNETO-ABSORPTION STUDY OF BARRIER IMPURITIES AND SCREENING IN GaAs/AlGaAs MULTIPLE QUANTUM WELLS

1987 ◽  
Vol 48 (C5) ◽  
pp. C5-239-C5-242 ◽  
Author(s):  
E. GLASER ◽  
B. V. SHANABROOK ◽  
R. J. WAGNER ◽  
R. L. HAWKINS ◽  
W. J. MOORE ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Far Infrared ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Absorption Study

V-Defect and Dislocation Analysis in InGaN Multiple Quantum Wells on Patterned Sapphire Substrate

2018 ◽  
Vol 787 ◽  
pp. 37-41
Author(s):  
Huan You Wang ◽  
Qiao Lai Tan ◽  
Gui Jin
Keyword(s):  
Quantum Wells ◽  
Strain Relaxation ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Cross Sectional ◽  
Patterned Sapphire Substrate ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Multi Quantum Well ◽  
Patterned Sapphire Substrates

InGaN/GaN multiquantum well (MQW) structures have been grown on cone-shaped patterned sapphire substrates (CPSS) by metalorganic chemical vapor deposition (MOCVD). From the transmission electron microscopy (TEM) results, we found that most of the threading dislocations (TDs) in the trench region of the CPSS were bent by lateral growth mode. Also the staircase-like TDs were observed near the slant region of the cone pattern, they converged at the slope of the cone patterned region by staircase-upward propagation, which seems to effectively prevent TDs from vertical propagation in the trench region. The associated dislocation runs up into the overgrown GaN layer and MQW, and some (a+c) dislocations were shown to decompose inside the multi-quantum well, giving rise to a misfit segment in the c-plane and a V-shape defect. From cross-sectional TEM, we found that all V defects are not always connected with TDs at their bottom, some V defects are generated from the stacking mismatch boundaries induced by stacking faults which are formed within the MQW due to the strain relaxation.

Integrated Rib Waveguide-Photodetector Using Si/Si1−xGex Multiple Quantum Wells for Long Wavelenghts

1991 ◽  
Vol 220 ◽  
Author(s):  
V. P. Kesan ◽  
P. G. May ◽  
G. V. Treyz ◽  
E. Bassous ◽  
S. S. Iyer ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Internal Quantum Efficiency ◽  
Optical Quality ◽  
Silicon Substrates ◽  
Multiple Quantum ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Long Wavelength ◽  
Response Bandwidth ◽  
Soi Substrates

ABSTRACTWe have investigated the structural, electrical, and optical quality of epitaxial Si and Si1−xGex films grown by MBE on SIMOX (Separation by IMplanted OXygen) silicon substrates. Epitaxial films grown on these SOI substrates have been characterized using planar and cross-sectional TEM, high resolution X-ray diffraction, SIMS, and Seeco chemical etching to delineate defects. We have fabricated Si/SiGe P-i-N photodetectors integrated with Si waveguides on SOI for long wavelength applications. Low reverse leakage current densities were seen in these device structures. The photodetector exhibited an internal quantum efficiency of 50% at 1.1 μm with a frequency response bandwidth of 2 GHz.

Far-infrared laser photoconductivity of n-GaAs multiple quantum wells in a pulsed magnetic field

1998 ◽  
Vol 246-247 ◽  
pp. 290-293 ◽  
Author(s):  
R.J. Heron ◽  
R.A. Lewis ◽  
A.V. Skougarevsky ◽  
R.P. Starrett ◽  
R.G. Clark ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Wells ◽  
Far Infrared ◽  
Infrared Laser ◽  
Pulsed Magnetic Field ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Far Infrared Laser

THE OBSERVATION OF THE MAGNETIC PHONON MODE IN MODULATION DOPED DILUTE Cd1-xMnxTe/Cd1-yMgyTe QUANTUM WELL STRUCTURE

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1568-1573
Author(s):  
LI-CHUN TUNG ◽  
YONG-JIE WANG ◽  
GRZEGORZ KARCZEWSKI
Keyword(s):  
Quantum Wells ◽  
Phonon Mode ◽  
Magnetic Order ◽  
Far Infrared ◽  
Spin Hamiltonian ◽  
Infrared Transmission ◽  
Phonon Modes ◽  
Modulation Doping ◽  
Mn Concentration ◽  
Absorption Mode

The CdMnTe/CdMgTe quantum wells have been a focus of interests for its novel magnetic and transport properties and applications in spintronics. We have carried out a systematic study over a series of CdMnTe quantum wells with a range of Mn concentration (0%–3.9%) and modulation doping. Far-infrared transmission spectra have revealed several new infrared-active modes which are both magnetic-field and Mn -concentration dependent. The absorption mode near 125cm-1 (B1) is possibly resulted from the magnetic-order-dependent phonon mode due to an ion-position dependent spin Hamiltonian, while the other two (M1 & M2) may be related to the CdTe optical phonon modes.

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