The Magnitude of the Piezoelectric Effect in InGaN Quantum Wells

1998 ◽  
Vol 512 ◽  
Author(s):  
Piotr Perlin ◽  
Christian Kisielowski ◽  
Laila Mattos ◽  
Noad A. Shapiro ◽  
Joachim Kruger ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Piezoelectric Effect ◽  
Blue Shift ◽  
Peak Position ◽  
Normal Band ◽  
Pumping Power ◽  
Piezoelectric Field ◽  
Band Tailing ◽  
Ingan Quantum Wells

ABSTRACTA photoluminescence from a multiquantum GaN/InxGa1−xN/GaN well structure (x varies between 0.1 to 0.4) was investigated at various temperatures, pumping powers. While the temperature dependence of the peak position indicates normal band to band character of radiative recombination, the large pumping power induced “blue”shift of the peak position (up to 200 meV) can be observed. This kind of shift cannot be easily explained by the band tailing effect but is most likely the result of the screening of the strain-induced piezoelectric field. By evaluating the theoretical values of the piezoelectric filelds in the quantum well, we can show that in order to account for the experimental results we have to assume the partial relaxation of the strain.

1.37 - 2.90 Micron Intersubband Transitions in GaN/AlN Superlattices

2006 ◽  
Vol 955 ◽  
Author(s):  
Eric Anthony DeCuir ◽  
Emil Fred ◽  
Omar Manasreh ◽  
Jinqiao Xie ◽  
Hadis Morkoc ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Bound States ◽  
Energy Levels ◽  
Three Dimensional ◽  
Blue Shift ◽  
Bound State ◽  
Peak Position ◽  
Multiple Quantum ◽  
Intersubband Transitions ◽  
Photovoltaic Mode

ABSTRACTIntersubband transitions in the spectral range of 1.37-2.90 °Cm is observed in molecular beam epitaxy grown Si-doped GaN/AlN multiple quantum wells using a Fourier-transform spectroscopy technique. A blue shift in the peak position of the intersubband transition is observed as the well width is decreased. A sample with a well width in the order of 2.4 nm exhibited the presence of three bound states in the GaN well. The bound state energy levels are calculated using a transfer matrix method. An electrochemical capacitance voltage technique is used to obtain the three dimensional carrier concentrations in these samples which further enable the calculation of the Fermi energy level position. Devices fabricated from these GaN/AlN quantum wells are found to operate in the photovoltaic mode.

scholarly journals The effects of indium concentration and well-thickness on the mechanisms of radiative recombination in InxGa1−xN quantum wells

2000 ◽  
Vol 5 (1) ◽  
Author(s):  
N. A. Shapiro ◽  
Piotr Perlin ◽  
Christian Kisielowski ◽  
L. S. Mattos ◽  
J. W. Yang ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Recombination ◽  
Chemical Properties ◽  
Major Effect ◽  
Atomic Scale ◽  
Luminescence Properties ◽  
Recombination Energy ◽  
Indium Concentration ◽  
Piezoelectric Field ◽  
And Chemical Properties

A correlation of the local indium concentration measured on an atomic scale with luminescence properties of InxGa1−xN quantum wells reveals two different types of recombination mechanisms. A piezoelectric-field based mechanism is shown to dominate in samples with thick wells (L > 3 nm) of low indium concentration (x < 0.15−0.20). Spatial indium concentration fluctuations dominate luminescence properties in samples of higher indium concentrations in thinner wells. Quantum confinement is shown to have a major effect on the radiative recombination energy. A model is presented that relates the experimentally measured nano scale structural and chemical properties of quantum wells to the characteristics of the luminescence.

Interband Transitions in GaInNAs/GaAs Single Quantum Wells

2002 ◽  
Vol 744 ◽  
Author(s):  
M. O. Manasreh ◽  
D. J. Friedman ◽  
W. Q. Ma ◽  
C. L. Workman ◽  
C. E. George ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Mole Fraction ◽  
Chemical Vapor ◽  
Blue Shift ◽  
Peak Position ◽  
Interband Transitions ◽  
Single Quantum ◽  
Pl Spectra ◽  
Vapor Deposition Technique ◽  
Pl Intensity

ABSTRACTPhotoluminescence (PL) spectra of interband transitions in GaInNAs/GaAs single quantum wells grown by metalorganic chemical vapor deposition technique on semi-insulating GaAs substrates were measured at 77 K for several samples grown with different In composition and dimethylhydrazine (DMH)/III ratios. The results show that the PL intensity increases as the In mole fraction is increased from 0 to 25%, but the PL intensity is degraded for samples with an In mole fraction of 30% or higher. The peak position energies of the PL spectra were investigated as a function of the DMH/III ratio. Thermal annealing effect induced a blue-shift in the PL spectra peak position energy in samples grown with high DMH/III ratio.

Temperature Dependence of the Linewidth and Peak Position of the Intersubband Infrared Absorption in GaAs/Al0.3Ga0.7As Quantum Wells

1990 ◽  
Vol 216 ◽  
Author(s):  
M. O. Manasreh ◽  
C. E. Stutz ◽  
K. R. Evans ◽  
F. Szmulowicz ◽  
D. W. Fischer
Keyword(s):  
Quantum Wells ◽  
Infrared Absorption ◽  
Dopant Concentration ◽  
Blue Shift ◽  
Peak Position ◽  
Multiple Quantum ◽  
Temperature Dependent ◽  
Optical Phonon Mode ◽  
Weakly Coupled ◽  
Absorption Technique

ABSTRACTThe linewidth and peak position (vo) of the intersubband transition (IT) in GaAs/Al0.3Ga0.7As multiple quantum wells are studied as a function of temperature using the infrared absorption technique. We find that electrons in the GaAs well are weakly coupled to the GaAs normal optical phonon mode. The total integrated area of IT absorption is found to be approximately constant in the samples that were doped in the well but temperature dependent in the samples that were doped in the barrier. We also find that vo increases as the temperature decreases. This blue shift is found to increase as the dopant concentration is increased. We calculated the absorption spectrum in a nonparabolic-anisotropic envelope function approximation including temperature dependent effective masses, nonparbolicity, conduction band offsets, the Fermi level, and lineshape broadening. Our results indicate that a large manybody correction, in particular an exchange interaction (Eexch) for the ground state, is necessary to account for the observed blue shift as the dopant concentration increases.

Piezoelectric field compensation in the InGaN quantum wells of GaN/InGaN/AlGaN LEDs structures: electroreflectance experiment

2010 ◽  
Vol 7 (7-8) ◽  
pp. 1863-1865 ◽  
Author(s):  
Lev Avakyants ◽  
Pavel Bokov ◽  
Anatoly Chervyakov ◽  
Alexander Yunovich ◽  
Elena Vasileva ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Piezoelectric Field ◽  
Ingan Quantum Wells

The Influence of Defects and Piezoelectric Fields on the Luminescence from InGaN/GaN Single Quantum Wells

2000 ◽  
Vol 639 ◽  
Author(s):  
S. J. Henley ◽  
D. Cherns
Keyword(s):  
Electron Microscope ◽  
Quantum Wells ◽  
Spatial Resolution ◽  
Blue Shift ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Plan View ◽  
Transmission Electron ◽  
Piezoelectric Field ◽  
Piezoelectric Fields

ABSTRACTHigh spatial resolution cathodoluminescence (CL) studies have been carried out on GaN/InGaN/(0001)GaN single quantum well (SQW) structures in a field emission scanning electron microscope at 5kV and temperatures down to 8K. Direct comparison of QW CL maps with transmission electron microscope studies of plan-view samples showed that edge type threading dislocations act as non-radiative recombination centers. Spectra taken from extended areas showed a progressive blue shift in the QW emission from around 460nm at low beam intensities to about 445nm as the beam intensity was increased. This effect which correlated with a decrease in the spatial resolution is interpreted as due to an increase in the diffusion length of carriers in the SQW due to a combination of screening of the piezoelectric field and band filling effects.

scholarly journals Determination of the piezoelectric field in InGaN quantum wells

2005 ◽  
Vol 86 (13) ◽  
pp. 131108 ◽  
Author(s):  
I. H. Brown ◽  
I. A. Pope ◽  
P. M. Smowton ◽  
P. Blood ◽  
J. D. Thomson ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Piezoelectric Field ◽  
Ingan Quantum Wells

A Role of the Built-in Piezoelectric Field in InGaN/AlGaN/GaN Multiple Quantum Wells in the Electroferlectance Experiments

2007 ◽  
Vol 1040 ◽  
Author(s):  
Pavel Bokov ◽  
Lev Avakyants ◽  
Mansur Badgutdinov ◽  
Anatoly Chervyakov ◽  
Stanislav Shirokov ◽  
...  
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Reverse Bias ◽  
Flip Chip ◽  
Blue Shift ◽  
Multiple Quantum ◽  
Reverse Bias Voltage ◽  
Light Emitting ◽  
Piezoelectric Field

AbstractThe influence of built in piezoelectric field in the light-emitting diodes based on InGaN/AlGaN/GaN heterostructures on the electroreflectance spectra have been studied. The structures were grown by MOCVD technology and «flip-chip» mounted. Light was emitted or reflected through sapphire substrate. The built in electric field in the structure was modulated by pulses of reverse bias from -6 to +1 V applied to the contacts of diode. Observed blue shift of spectral line from InGaN/GaN multiply quantum wells region with the increasing reverse bias voltage has been explained as the result of lowering of the electric field in the quantum well.

scholarly journals Piezoelectric Field Effect on Optical Properties of GaN/GaInN/AlGaN Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 628-633 ◽  
Author(s):  
Jin Seo Im ◽  
H. Kollmer ◽  
O. Gfrörer ◽  
J. Off ◽  
F. Scholz ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Field Effect ◽  
Blue Shift ◽  
Asymmetric Structure ◽  
Band Bending ◽  
Time Resolved ◽  
Model Calculations ◽  
Piezoelectric Field ◽  
Strained Quantum Well

We designed and studied two sample groups: first, GaInN/AlGaN/GaN quantum wells with asymmetric barrier structure and secondly, GaInN/GaN quantum wells with asymmetrically doped barriers. Time-resolved measurements on the asymmetric structure reveal an enhanced oscillator strength when the AlGaN barrier is on top of the GaInN quantum well, indicating a better carrier confinement in such a structure. The photoluminescence emission energy of the GaInN/GaN quantum well with doped GaN barriers shifts towards higher energy than that of undoped samples due to screening, but only when the GaN barrier layer below the quantum well is doped. In contrast, the sample where only a GaN cap layer above the quantum well is doped, shows no blue-shift. These results, showing asymmetries in GaInN/GaN quantum wells, provide confirming evidence of the piezoelectric field effect and allow us to determine the sign of the piezoelectric field, which points towards the substrate in a compressively strained quantum well. Furthermore, we performed model calculations of the global band bending and the screening effect, which consistently explain our experimental findings.

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