Similarities in the Optical Properties of Hexagonal and Cubic InGaN Quantum Wells

2001 ◽  
Vol 693 ◽  
Author(s):  
S. F. Chichibu ◽  
M. Sugiyama ◽  
T. Onuma ◽  
T. Kuroda ◽  
A. Tackeuchi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Intrinsic Property ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Exciton Localization ◽  
Peak Energy ◽  
Stretched Exponential Decay ◽  
Ingan Quantum Wells

AbstractOptical properties of fully-strained wurtzite and zincblende InxGa1-xN/GaN multiple quantum well (MQW) structures were compared to discuss the origin of exciton localization. In contrast to the hexagonal InGaN MQWs, the photoluminescence (PL) peak energy of cubic InGaN MQWs showed a moderate blueshift with decreasing well thickness, L, and low-temperature PL decay time of the cubic MQWs did not depend strongly on L. The results imply that the wavefunction overlap in cubic InGaN MQWs was not reduced compared to the hexagonal ones, since they do not suffer from the electric field normal to the QW plane due either to spontaneous or piezoelectric polarization. Both MQWs exhibited a large and composition-dependent bandgap bowing, and time-resolved PL (TR-PL) signals showed a stretched-exponential decay even at room temperature. The exciton localization is considered to be an intrinsic property of InGaN.

Optical properties of GaN Photonic Crystal Membrane Nanocavities at Blue Wavelengths

2005 ◽  
Vol 892 ◽  
Author(s):  
Yong-Seok Choi ◽  
Cedrik Meier ◽  
Rajat Sharma ◽  
Kevin Hennessy ◽  
Elaine D. Haberer ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photonic Crystal ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Light Extraction ◽  
Design Parameters ◽  
Multiple Quantum ◽  
Membrane Structures ◽  
High Q ◽  
Q Factors

AbstractWe have investigated the design parameters for high-Q photonic-crystal (PC) bandgap modes in the emission wavelengths of InGaN/GaN multiple quantum wells. We demonstrate experimental schemes to realize 2D triangular-lattice PC membrane structures, which is essential to obtain photonic bandgap (PBG) modes, and the optical properties of L7 membrane nanocavities that consist of seven missing holes in the Γ-K direction. L7 cavities show pronounced resonances with Q factors of 300 to 800 in the PBG as well as the enhancement of light extraction of the broad InGaN/GaN multiple-quantum-well emission by the 2D PBG.

Structural and Optical Properties of InGaN/GaN Multi-Quantum Well Structures with Different Indium Compositions

2003 ◽  
Vol 764 ◽  
Author(s):  
Chang-Soo Kim ◽  
Sam-Kyu Noh ◽  
Kyuhan Lee ◽  
Sunwoon Kim ◽  
Jay P. Song
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Lattice Relaxation ◽  
Multiple Quantum ◽  
Structural And Optical Properties ◽  
Rich Region ◽  
Quantum Well Structures ◽  
Peak Intensity ◽  
Peak Energy ◽  
Multi Quantum Well

AbstractThe structural and optical properties of InGaN/GaN multiple quantum wells (MQWs) grown on sapphire by MOCVD have been investigated using high-resolution XRD, PL and TEM. The samples consisted of 10 periods of InGaN wells with 6.5nm thickness. The designed indium compositions were 15, 20, 25 and 30% (samples C15, C20, C25, C30, respectively). The thickness of GaN barrier was 7.5nm. The MQW in sample C15 maintained lattice coherency with the GaN epilayer underneath, the MQWs in the other samples, however, experienced lattice relaxation. The crystallinity of the samples decreased considerably with In concentration. As In composition increased, PL peak energy showed a red-shift, and the FWHM of the peaks increased. The increase in the FWHM is attributed to the defects due to the lattice relaxation. For C25 the PL peak intensity increased sharply in spite of the defects due to the lattice relaxation of the sample. It is concluded that the results are related to the In-rich region due to indium phase separation which was observed by TEM image.

OPTICAL PROPERTIES AND CARRIER DYNAMICS IN ASYMMETRIC COUPLED InGaN MULTIPLE QUANTUM WELLS

2013 ◽  
Vol 06 (02) ◽  
pp. 1350021 ◽  
Author(s):  
GUO-EN WENG ◽  
BAO-PING ZHANG ◽  
MING-MING LIANG ◽  
XUE-QIN LV ◽  
JIANG-YONG ZHANG ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Energy Levels ◽  
Excitation Power ◽  
Equation Model ◽  
Carrier Dynamics ◽  
Multiple Quantum ◽  
Carrier Distribution ◽  
Time Resolved ◽  
Coupled Quantum Wells

Optical properties and carrier dynamics of InGaN/GaN asymmetric coupled quantum wells (ACQWs) are studied by excitation-power-dependent photoluminescence (PL), photoreflectance (PR) and time-resolved PL (TRPL) experiments. Under weak excitations, only the emission from the widest well is observed due to the tunneling from narrower to wider wells. Under strong excitations, the carrier distribution becomes more uniform and an enhanced emission from the mid well (2.5 nm well) is observed. Dependence of the PL intensity on excitation power is well explained by a rate equation model. The energy levels in the ACQW structure are clearly revealed by PR measurements and are in good agreement with calculations. Our results indicate that the enhanced emission from the mid well is ascribed to "reverse tunneling" from 3.0 to 2.5 nm well, which is confirmed by TRPL experiments.

Time-resolved photoluminescence studies of InGaN/GaN multiple quantum wells

1997 ◽  
Vol 2 ◽  
Author(s):  
J. Allègre ◽  
P. Lefebvre ◽  
S. Juillaguet ◽  
W. Knap ◽  
J. Camassel ◽  
...  
Keyword(s):  
Low Temperature ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Stimulated Emission ◽  
Multiple Quantum ◽  
Nitrogen Laser ◽  
Energy Position ◽  
Blue Band ◽  
Time Resolved ◽  
Decay Times

We report both cw and time resolved optical investigations performed on an InGaN/GaN multiple quantum well grown by MOVPE on <0001>-oriented sapphire substrate. At low temperature we find a strong “blue” luminescence band, of which energy position corresponds well with the wavelength of stimulated emission when excited with a nitrogen laser. We show that this PL band appears systematically red-shifted with respect to the QWs features, which supports a standard picture of fluctuations of the indium composition. Coming to the time-resolved data, we find at low temperature at least two “blue” band components which are both associated with long decay times (up to 4-5 ns at 8K). The decay time is temperature dependent and, when rising the temperature, the recombination rate increases. At room temperature, we reach typical values in the range ~100 to 500 ps.

Observation of Intersubband Absorption in Boron δ-Doped Si Layers

1991 ◽  
Vol 220 ◽  
Author(s):  
J. S. Park ◽  
R. P. G. Karunasiri ◽  
K. L. Wang ◽  
Y. J. Mii ◽  
J. Murray
Keyword(s):  
Quantum Wells ◽  
Infrared Absorption ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Many Body ◽  
Ir Detectors ◽  
Boron Doped ◽  
Peak Energy ◽  
Ftir Spectrometer ◽  
Experimental Values

ABSTRACTStrong hole intersubband infrared absorption in δ-doped Si multiple quantum wells is observed. The structures consist of 10 periods of boron doped Si quantum wells and undoped Si barriers. Near 100 % infrared absorption is measured by FTIR spectrometer using waveguide structures. Absorption peaks ranging between 3–7 μm are measured, and these peaks can be tuned by varying the doping concentration in the δ-doped layer. Polarization dependence has been verified to agree with the intersubband selection rule. The estimated peak energy positions using a self-consistency calculation are considerably lower than experimental values, probably due to a large exchange energy of many body effects. This observation suggests multiple quantum well IR detectors using Si- technology.

Interface Roughness of Quantum Wells Studied by Time-Resolved Photoluminescence

1989 ◽  
Vol 148 ◽  
Author(s):  
H. X. Jiang ◽  
P. Zhou ◽  
S. A. Solin ◽  
G. Bai
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Delay Time ◽  
Interface Roughness ◽  
Multiple Quantum ◽  
Exciton Peak ◽  
Exciton Luminescence ◽  
Roughness Effects ◽  
Time Resolved ◽  
Time Resolved Photoluminescence

ABSTRACTOptical properties of GaAs-Al0 5Ga0 5As multiple quantum wells affected by interface roughness have been investigated by timeresolved photoluminescence. The interface roughness affects on exciton dynamics is shown to be more complicated than those previously well studied line-width broadening of exciton transitions. A two-exponential decay of exciton luminescence and exciton peak shifting with increasing delay time have been observed. These observations have been successfully interpreted in terms of the interface roughness effects.

scholarly journals Impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN quantum wells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
A. A. Roble ◽  
S. K. Patra ◽  
F. Massabuau ◽  
M. Frentrup ◽  
M. A. Leontiadou ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Well ◽  
Quantum Wells ◽  
Three Dimensional ◽  
Growth Direction ◽  
Electronic And Optical Properties ◽  
Exciton Localization ◽  
Peak Energy ◽  
Coulomb Effects ◽  
The Impact

AbstractWe report on a combined theoretical and experimental study of the impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of $$c$$c-plane GaN/AlGaN multi-quantum well systems. The presence of carrier localization effects in this system was demonstrated by experimental observations, such as the “S-shape” temperature dependence of the photoluminescence (PL) peak energy, and non-exponential PL decay curves that varied across the PL spectra at 10 K. A three-dimensional modified continuum model, coupled with a self-consistent Hartree scheme, was employed to gain insight into the electronic and optical properties of the experimentally studied $$c$$c-plane GaN/AlGaN quantum wells. This model confirmed the existence of strong hole localization arising from the combined effects of the built-in polarization field along the growth direction and the alloy fluctuations at the quantum well/barrier interface. However, for electrons these localization effects are less pronounced in comparison to the holes. Furthermore, our calculations show that the attractive Coulomb interaction between electron and hole results in exciton localization. This behavior is in contrast to the picture of independently localized electrons and holes, often used to explain the radiative recombination process in $$c$$c-plane InGaN/GaN quantum well systems.

Impact of exciton localization on the optical properties of non-polarM-plane In0.1Ga0.9N/GaN multiple quantum wells

2003 ◽  
Vol 240 (2) ◽  
pp. 360-363 ◽  
Author(s):  
Yue Jun Sun ◽  
Oliver Brandt ◽  
Sven Cronenberg ◽  
Holger T. Grahn ◽  
Klaus H. Ploog
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Exciton Localization

scholarly journals Investigations on the Optical Properties of InGaN/GaN Multiple Quantum Wells with Varying GaN Cap Layer Thickness

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Xiaowei Wang ◽  
Feng Liang ◽  
Degang Zhao ◽  
Zongshun Liu ◽  
Jianjun Zhu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Layer Thickness ◽  
Stark Effect ◽  
Chemical Vapor ◽  
Multiple Quantum ◽  
Three Samples ◽  
Measurement Results ◽  
Cap Layer ◽  
The Difference

Abstract Three InGaN/GaN MQWs samples with varying GaN cap layer thickness were grown by metalorganic chemical vapor deposition (MOCVD) to investigate the optical properties. We found that a thicker cap layer is more effective in preventing the evaporation of the In composition in the InGaN quantum well layer. Furthermore, the quantum-confined Stark effect (QCSE) is enhanced with increasing the thickness of GaN cap layer. In addition, compared with the electroluminescence measurement results, we focus on the difference of localization states and defects in three samples induced by various cap thickness to explain the anomalies in room temperature photoluminescence measurements. We found that too thin GaN cap layer will exacerbates the inhomogeneity of localization states in InGaN QW layer, and too thick GaN cap layer will generate more defects in GaN cap layer.

Optical properties of extended and localized states in m-plane InGaN quantum wells

2013 ◽  
Vol 102 (10) ◽  
pp. 101102 ◽  
Author(s):  
S. Marcinkevičius ◽  
K. M. Kelchner ◽  
S. Nakamura ◽  
S. P. DenBaars ◽  
J. S. Speck
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Localized States ◽  
Ingan Quantum Wells
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