scholarly journals Impact of Alloy-Disorder-Induced Localization on Hole Diffusion in Highly Excited c -Plane and m -Plane ( In , Ga ) N Quantum Wells

2020 ◽  
Vol 14 (5) ◽  
Author(s):  
Ramūnas Aleksiejūnas ◽  
Kazimieras Nomeika ◽  
Oleg Kravcov ◽  
Saulius Nargelas ◽  
Leah Kuritzky ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Alloy Disorder

UV Emission Mechanisms in Quaternary AlInGaN Epilayers and Multiple Quantum Wells

2002 ◽  
Vol 722 ◽  
Author(s):  
Mee-Yi Ryu ◽  
C. Q. Chen ◽  
E. Kuokstis ◽  
J. W. Yang ◽  
G. Simin ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diode ◽  
Chemical Vapor ◽  
Excitation Power ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
Excitation Power Density ◽  
Light Emitting ◽  
Uv Emission ◽  
Alloy Disorder

AbstractWe present the results on investigation and analysis of photoluminescence (PL) dynamics of quaternary AlInGaN epilayers and AlInGaN/AlInGaN multiple quantum wells (MQWs) grown by a novel pulsed metalorganic chemical vapor deposition (PMOCVD). The emission peaks in both AlInGaN epilayers and MQWs show a blueshift with increasing excitation power density. The PL emission of quaternary samples is attributed to recombination of carriers/excitons localized at band-tail states. The PL decay time increases with decreasing emission photon energy, which is a characteristic of localized carrier/exciton recombination due to alloy disorder. The obtained properties of AlInGaN materials grown by a PMOCVD are similar to those of InGaN. This indicates that the AlInGaN system is promising for ultraviolet applications such as the InGaN system for blue light emitting diode and laser diode applications.

Time-Resolved Photoluminescence of GaN / Ga0.93Al0 .07N Quantum Wells

1997 ◽  
Vol 482 ◽  
Author(s):  
P. Lefebvre ◽  
J. Allègre ◽  
B. Gil ◽  
A. Kavokine ◽  
H. Mathieu ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Radiative Lifetime ◽  
Temperature Limit ◽  
Multiple Quantum ◽  
Carrier Localization ◽  
Substantial Variation ◽  
Time Resolved ◽  
Potential Fluctuations ◽  
Alloy Disorder ◽  
Time Resolved Photoluminescence

AbstractThe recombination dynamics of excitons in GaN / Ga0.93Al0.07N multiple quantum wells is studied versus lattice temperature. The average decay time of photoluminescence measured at 8K is of ∼330 ps, with a substantial variation of times within the emission line. This is interpreted in terms of carrier localization due to alloy disorder and to well width and depth variations. The radiative lifetime τr of excitons in the wells is found to increase linearly with temperature, with ∂τr / ∂T = 20.5 ± 0.7 ps.K−1. The radiative lifetime of free excitons in the low-temperature limit is deduced to be 2.4 ps, consistent with a longitudinal-transverse splitting ћωLT in GaN of 0.6 meV, in excellent agreement with recent estimations. The ratio of the lifetimes of localized and free excitons is found coherent with the picture of electrons and holes independently localized on short-range defects, instead of excitons localized as a whole on long-range potential fluctuations.

Doping-Dependent Nonlinear Electron Mobility in GaAs|In-=SUB=-x-=/SUB=-Ga-=SUB=-1-x-=/SUB=-As Coupled Quantum-Well Pseudo-Morphic MODFET Structure

2020 ◽  
Vol 54 (7) ◽  
pp. 676
Author(s):  
S.R. Panda ◽  
A. Sahu ◽  
S. Das ◽  
A.K. Panda ◽  
T. Sahu
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electron Mobility ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Energy Levels ◽  
Interface Roughness ◽  
Double Quantum ◽  
Double Quantum Well ◽  
Alloy Disorder

We analyze the asymmetric delta-doping dependence of nonlinear electron mobility μ of GaAs|InxGa1-xAs double quantum-well pseudo-morphic modulation doped field-effect transistor structure. We solve the Schrodinger and Poisson's equations self-consistently to obtain the sub-band energy levels and wave functions. We consider scatterings due to the ionized impurities (IMP), alloy disorder (AL), and interface roughness (IR) to calculate μ for a system having double sub-band occupancy, in which the inter-sub-band effects play an important role. Considering the doping concentrations in the barriers towards the substrate and surface sides as Nd1 and Nd2, respectively, we show that variation of Nd1 leads to a dip in μ near Nd1=Nd2, at which the resonance of the sub-band states occurs. A similar dip in μ as a function of Nd1 is also obtained at Nd1=Nd2 by keeping (Nd1+Nd2) unchanged. By increasing the central barrier width and well width, the dip in μ becomes sharp. We note that even though the overall μ is governed by the IMP- and AL-scatterings, the dip in μ is mostly affected through substantial variation of the sub-band mobilities due to IR-scattering near the resonance. Our results of nonlinear electron mobility near the resonance of sub-band states can be utilized for the performance analysis of GaAs|InGaAs pseudo-morphic quantum-well field-effect transistors. Keywords: asymmetric double quantum wells, GaAs|InxGa1-xAs structures, nonlinear electron mobility, pseudo-morphic HEMT structures, resonance of sub-band states.

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