Single Quantum Well Heterostructures of MgZnO/ZnO/MgZnO on C-Plane Sapphire

2000 ◽  
Vol 623 ◽  
Author(s):  
S. Choopun ◽  
D. M. Chalk ◽  
W. Yang ◽  
R. D. Vispute ◽  
S. B. Ogale ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Reference Sample ◽  
Blue Shift ◽  
Growth Conditions ◽  
Interface Roughness ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Quantum Size ◽  
Well Model

AbstractThe single quantum well heterostructures of MgZnO/ZnO/MgZnO were grown on c-plane sapphire substrate by pulsed laser deposition. The well width was varied from 10 nm to 40 nm by controlling the deposition rate via number of laser pulsed on ZnO target. Using photoluminescence spectroscopy, we have observed a blue shift with respect to a thick ZnO reference sample when the well width was decreased. These results were fitted with calculations based on the simple square well model using the appropriate electron and holes effective masses. The quantized-energy and band offset as a function of well width, growth conditions, interface roughness, and possible quantum size effects on the quantum wells are discussed.

Effect of Thermal Annealing on the Photoluminescence Properties of a GaInNAs/GaAs Single Quantum Well

2000 ◽  
Vol 639 ◽  
Author(s):  
Laurent Grenouillet ◽  
Catherine Bru-Chevallier ◽  
Gérard Guillot ◽  
Philippe Gilet ◽  
Philippe Ballet ◽  
...  
Keyword(s):  
Quantum Well ◽  
Thermal Annealing ◽  
Low Temperatures ◽  
Blue Shift ◽  
Emission Peak ◽  
Single Quantum ◽  
Photoluminescence Properties ◽  
Single Quantum Well ◽  
Peak Energy ◽  
Strong Blue Shift

ABSTRACTWe report on the effect of thermal annealing on the photoluminescence properties of a Ga0.65In0.35N0.02As0.98/GaAs single quantum well. Thermal annealing is shown to decrease the strong nitrogen-induced localization effects observed at low temperatures and to reduce the full width at half maximum of the emission peak. It also induces a strong blue shift of the emission peak energy, which is thought not to arise from an In-Ga interdiffusion alone, as it is much larger than in a nitrogen-free reference single quantum well.

Low Temperature Growth of Gaas Quantum Well Lasers by Modulated Beam Epitaxy

1991 ◽  
Vol 228 ◽  
Author(s):  
S. Xin ◽  
K. F. Longenbach ◽  
C. Schwartz ◽  
Y. Jiang ◽  
W. I. Wang
Keyword(s):  
Low Temperature ◽  
Quantum Well ◽  
Substrate Temperature ◽  
Quantum Wells ◽  
High Growth ◽  
Quantum Well Lasers ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Temperature Growth ◽  
Low Temperature Growth

ABSTRACTGaAs single quantum well lasers have been successfully grown at low temperatures by a modulated beam epitaxy process in which the Al/Ga flux is held constant while the As flux is periodically shut off to produce a metal-rich surface. Devices grown at a substrate temperature of 500 °C exhibit threshold current densities below 1 kA/cm2. This value is lower than normally grown low temperature lasers and is the lowest achieved by any low substrate temperature growth technique. In addition, low temperature (10 K) photoluminescence of single quantum wells grown with this technique exhibit full-width half maximum values, comparable to that attainable by higher temperature growth techniques. The improved quality of these low temperature grown quantum structures is attributed to both a smoothing of the growth front and a reduction of excess As during the modulated beam epitaxy process. The high growth rates and less frequent shutter operation of this technique make it a more practical than migration enhanced epitaxy or atomic layer epitaxy for low temperature growth.

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.

Nonlinear optical properties in the laser-dressed two-level AlxGa1−xN/GaN single quantum well

2018 ◽  
Vol 32 (04) ◽  
pp. 1850032 ◽  
Author(s):  
Monalisa Panda ◽  
Tapaswini Das ◽  
B. K. Panda
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Effective Mass ◽  
Nonlinear Optical ◽  
Energy Levels ◽  
Internal Electric Field ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Increase With Increase

The electronic states in the laser-dressed hexagonal and cubic Al[Formula: see text]Ga[Formula: see text]N/GaN single quantum wells are calculated using the effective mass equation. The hexagonal single quantum well contains an internal electric field due to spontaneous and piezoelectric polarizations. The effective mass equation is solved by the finite difference method. The energy levels in both cubic and hexagonal laser-dressed wells are found to increase with increase in laser dressing as the effective well widths in both the wells increase. The intersubband energy spacing between first excited state and ground state increases in the cubic quantum well, whereas it decreases in the hexagonal well due to the presence of internal electric field in it. Using the compact density matrix method with iterative procedure, first-, second- and third-order nonlinear optical susceptibilities in the laser-dressed quantum well are calculated taking only two levels. While the susceptibilities in the hexagonal well are found to get red shifted, the susceptibilities in the cubic well are blue shifted.

Growth of High Quality (In,Ga,Al)N/GaN Heterostructure Materials and Devices by Atmospheric Pressure MOCVD

1996 ◽  
Vol 423 ◽  
Author(s):  
S. P. Denbaars ◽  
S. Keller ◽  
B. P. Keller ◽  
Y. F. Wu ◽  
D. Kapolnek ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Atmospheric Pressure ◽  
Impurity Level ◽  
Single Quantum ◽  
High Quality ◽  
Single Quantum Well ◽  
Background Impurity ◽  
Direct Band ◽  
Gan Heterostructure

AbstractUsing atmospheric pressure MOCVD we have obtained high quality InGaN/GaN and AlGaN/GaN heterostructure materials and devices. For nominally undoped 4 μm thick GaN films, we obtained 300 K mobilities of 780 cm2/Vs and an unintentional background impurity level of n300K = 6*1016 cm−3. For InGaN/GaN heterostructures we have obtained direct band-edge transitions with FWHM as narrow as 7.9 nm (59 meV) for 50Å thick In0.16Ga0.84N quantum wells at 300K, which is the among the best reported values. The quantum wells display energy shifts towards shorter wavelength with decreasing well thickness, and the shift agrees with predicted quantum effects. These materials have been incorporated into InGaN single quantum well LEDs that emit at 450 nm. In addition AlGaN/GaN heterostructure materials have been incorporated into HFETs and MODFETs. Gate-drain breakdown voltage well exceeding 100 V, and extrinsic transconductance gm of up to 140 mS/mm were realized in the MODFET.

scholarly journals Влияние конструкции активной области и волновода на характеристики лазеров на основе структур квантовые ямы-точки InGaAs/GaAs

2021 ◽  
Vol 55 (3) ◽  
pp. 256
Author(s):  
Ю.М. Шерняков ◽  
Н.Ю. Гордеев ◽  
А.С. Паюсов ◽  
А.А. Серин ◽  
Г.О. Корнышов ◽  
...  
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Ground State ◽  
Cavity Length ◽  
Blue Shift ◽  
Optical Confinement ◽  
Single Quantum Well ◽  
Lasing Wavelength ◽  
Optical Region ◽  
Emitting Lasers

We study edge-emitting lasers with the active area based on novel InGaAs/GaAs quantum heterostructures of transitional dimensionality referred to as quantum well-dots, which are intermediate in properties between quantum wells and quantum dots. We show that the rate of the lasing wavelength blue-shift occurring with the reduction in cavity length decreases with an increase in the number of quantum well-dot layers in the active region and the optical confinement factor. In the laser based on 10 quantum well-dot layers, the position of the lasing wavelength remains in the optical region corresponding to the emission from the ground state down to the cavity lengths as short as 100 μm. In the devices based on a single quantum well-dot layer and/or with low optical confinement factor, lasing directly switches from the ground state to the GaAs waveguide states omitting excited state lasing with decrease in cavity length below 200 μm. Such an effect has not been observed in quantum well and quantum dot lasers and is attributed to the abnormally low density of excited states in quantum well-dots.

Optical and Electrical Characteristics of Single-Quantum-Well InGaN Light-Emitting Diodes

1996 ◽  
Vol 449 ◽  
Author(s):  
Piotr Perlin ◽  
Marek Osiński ◽  
Petr G Eliseev
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Energy Gap ◽  
Green Light ◽  
Temperature Shift ◽  
Blue Shift ◽  
Single Quantum ◽  
Single Quantum Well ◽  
Light Emitting ◽  
Increasing Temperature

ABSTRACTWe have studied the electroluminescence and photoluminescence of Nichia single-quantum-well Al0.2Ga0.8N/In0.45Ga0.55N/GaN green light-emitting diodes over a broad range of temperatures (15-300 K) and currents (0.2 μA - 2 A). The most striking behavior is an anomalous temperature shift of both photo- and electroluminescence, with the emission peak moving towards higher energies with increasing temperature. This blue shift is opposite to that of the energy gap of the active layer, which practically excludes interband transitions as responsible for the observed optical transitions. We suggest that population effects within the band tails can account for the observed anomaly. We also determined that the current flowing through the p-n junction is dominated by carrier tunneling, the omnipresent effect in the GaN-based optoelectronic devices.

Sign in / Sign up

Export Citation Format

Share Document