LASER-INDUCED ADIABATIC POPULATION TRANSFER IN ASYMMETRIC QUANTUM WELLS

NANO ◽  
2009 ◽  
Vol 04 (05) ◽  
pp. 289-297
Author(s):  
MONICA GAMBHIR ◽  
SIDDHARTHA LAHON ◽  
PRADEEP KUMAR JHA ◽  
MAN MOHAN
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
High Efficiency ◽  
Proper Time ◽  
Logic Gates ◽  
Double Quantum ◽  
Population Transfer ◽  
Quantum Logic Gates ◽  
Double Quantum Well ◽  
The Impact

The basic technique of stimulated Raman adiabatic passage for laser-induced adiabatic population transfer between discrete quantum states of an asymmetric double quantum well has been used in our study. The results show that the proper time-delay, overlap, and detuning of two pulses allows the coherent transfer between the states of a double quantum well system, leading to the possibility of implementation of semiconductor–based quantum logic gates and high efficiency optical switches. The impact of phase relaxation on the population transfer efficiency is also studied.

Electronic States in Cd1−xZnxTe/CdTe Strained Layer Coupled Double Quantum Wells and their Photoluminescence

1994 ◽  
Vol 358 ◽  
Author(s):  
Tiesheng Li ◽  
H. J. Lozykowski
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Lattice Mismatch ◽  
Electronic States ◽  
Double Quantum ◽  
Strain Effect ◽  
Strained Layer ◽  
Quantum Well Structure ◽  
Double Quantum Well ◽  
Theoretical Investigations

ABSTRACTExperimental and theoretical investigations of electronic states in a strained-layer CdTe/CdZnTe coupled double quantum well structure are presented. The optical properties of this lattice mismatched heterostructure were characterized by photoluminescence (PL), PL excitation and polarization spectroscopies. The influence of electrical field on exciton states in the strained layer CdTe/CdZnTe coupled double quantum well structure is experimentally studied. The confined electronic states were calculated in the framework of the envelope function approach, taking into account the strain effect induced by the lattice-mismatch. Experimental results are compared with the calculated transition energies.

A THEORETICAL AND EXPERIMENTAL STUDY OF ELECTRONIC CONFINEMENT, COUPLING, AND TRANSLAYER INTERACTION IN NOBLE-METAL QUANTUM-WELL STRUCTURES

1994 ◽  
Vol 08 (18) ◽  
pp. 1075-1096 ◽  
Author(s):  
W. E. MCMAHON ◽  
T. MILLER ◽  
T.-C. CHIANG
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Noble Metal ◽  
Experimental Studies ◽  
Surface States ◽  
Double Quantum ◽  
Multilayer Systems ◽  
Quantum Well Structures ◽  
Double Quantum Well ◽  
Bloch Electrons

Noble-metal multilayer systems have been grown and examined with angle-resolved photoemission. Surface states, and single and double quantum wells have been studied experimentally; the results can be explained with a simple theoretical model based upon Bloch electrons. In this paper, we will present our model and then give a description of some experimental studies which utilize the model. In particular, we will consider double-quantum-well systems which can be used to examine basic aspects of electronic confinement, layer–layer coupling, and translayer interaction through a barrier.

Effect of Electric Fields in Coupled Double Quantum Wells

1987 ◽  
Vol 102 ◽  
Author(s):  
Y. J. Chen ◽  
Emil S. Koteles ◽  
B. Elman ◽  
C. A. Armiento
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Stark Effect ◽  
Double Quantum ◽  
Single Quantum Well ◽  
Quantum Confined Stark Effect ◽  
Quantum Well Structure ◽  
Double Quantum Well ◽  
Novel Structure

ABSTRACTWe present a detailed experimental study of the influence of electric fields on exciton states in a GaAs/AlGaAs coupled double quantum well structure and discuss the advantages of using this novel structure. The coupling of electronic states in the two quantum wells, due to the narrowness of the barrier between them, leads to an enhancement of the quantum-confined Stark effect (by as much as five times that of the single quantum well case). From the measured energies of the exciton transitions, splittings of the levels in a coupled double quantum well structure were derived without recourse to a theoretical model.

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.

1.95 μm Compressively Strained Ingaas/Ingaasp Quantum Well DFB Laser With Low Threshold

1997 ◽  
Vol 484 ◽  
Author(s):  
Jie Dong ◽  
Akinoi Ubukata ◽  
Koh Matsumoto
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Chemical Vapor ◽  
Double Quantum ◽  
Maximum Output ◽  
Quantum Well Structures ◽  
Double Quantum Well ◽  
Different Temperatures ◽  
Dfb Laser ◽  
Strained Quantum Well

AbstractIn this study, we demonstrate the growth of highly compressively strained InGaAs/JnGaAsP quantum well structures with large well thiclmess by low pressure metalorganic chemical vapor deposition for extending the emission wavelength of lasers. By comparing the photolumineswnce characteristics of quantum wells grown at different temperatures, it is clarified that a relatively high quality quantum well layer emittig at 2.0 μ, can be obtained at a growth temperature of 650°C. 1.95-μm-wavelength InGaAs/InGaAsP highly compressively strained quantum well DFB laser for laser spectroscopy monitors was also fabricated. Double quantum-well DFB laser operating at 1.95 μm exhibits threshold currents as low as 6 mA and 6.2 mW maximum output powers. 2.04-μm-wavelength DFB laser is also described.

Sign of the Piezoelectric Field in Asymmetric GaInN/AlGaN/GaN Single and Double Quantum Wells on SiC

1999 ◽  
Vol 595 ◽  
Author(s):  
Jin Seo Im ◽  
A. Hangleiter ◽  
J. Off ◽  
F. Scholz
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Oscillator Strength ◽  
Double Quantum ◽  
Barrier Structure ◽  
Time Resolved ◽  
Double Quantum Well ◽  
First Case ◽  
Algan Barrier ◽  
Piezoelectric Field

AbstractWe study both GaInN/GaN/AlGaN quantum wells with an asymmetric barrier structure grown on SiC substrate and GaN/AlGaN asymmetric double quantum well (ADQW) structures. In the first case, a time-resolved study reveals an enhanced oscillator strength when the AlGaN barrier is on top of the GaInN quantum well. In comparison to our previous study of the same structure grown on sapphire, we find that the sign of the field is the same in both cases: the field points towards the substrate. In the case of ADQW, we observed not only intrawell transitions of both a 4 nm and a 2 nm QW separated by a 2.5 nm AlGaN barrier but also an interwell transition between the two QWs in the photoluminescence. The lifetimes and emission energies of the transitions can be well explained by the existence of the piezoelectric field built in the QWs.

Single electron tunneling in double and triple quantum wells

2016 ◽  
Vol 30 (13) ◽  
pp. 1642011 ◽  
Author(s):  
I. Filikhin ◽  
A. Karoui ◽  
B. Vlahovic
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Mirror Symmetry ◽  
Electron Tunneling ◽  
Coupled System ◽  
Double Quantum ◽  
Strain Effect ◽  
Electron Localization ◽  
Double Quantum Well ◽  
Weakly Coupled System

Electron localization and tunneling in laterally distributed double quantum well (DQW) and triple quantum well (TQW) are studied. Triangular configuration for the TQWs as well as various quantum well (QW) shapes and asymmetry are considered. The effect of adding a third well to a DQW is investigated as a weakly coupled system. InAs/GaAs DQWs and TQWs were modeled using single subband effective mass approach with effective potential simulating the strain effect. Electron localization dynamics in DQW and TQW over the whole spectrum is studied by varying the inter-dot distances. The electron tunneling appeared highly sensitive to small violations of the DQW mirror symmetry. We show that the presence of a third dot increases the tunneling in the DQW. The dependence of the tunneling in quantum dot (QD) arrays on inter-dot distances is also discussed.

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