Transient photoluminescence studies of coupled double-quantum wells

1989 ◽  
Vol 67 (4) ◽  
pp. 315-320
Author(s):  
S. Charbonneau ◽  
M. L. W. Thewalt ◽  
Emil S. Koteles ◽  
B. Elman
Keyword(s):  
Experimental Study ◽  
Electric Field ◽  
Quantum Wells ◽  
Lower Energy ◽  
Wave Functions ◽  
Double Quantum ◽  
Double Quantum Well ◽  
Field Dependent ◽  
Single Well ◽  
Photoluminescence Studies

We have undertaken a detailed experimental study of the electric-field-dependent coupling between two identical GaAs quantum wells separated by a narrow AlGaAs barrier using photoluminescence (PL), transient PL, and PL excitation spectroscopy. It was found that the coupling of the wave functions in a coupled double-quantum well (CDQW) structure produces a splitting of the single-well levels. The influence of an electric field on the exciton states in such a structure showed clear evidence that both intrawell and interwell exciton transitions occur. Furthermore, the effect of rapid thermal annealing (RTA) on these CDQW structures with and without SiO2 cap layers was also studied. While RTA without a capping layer produced only minor changes in the PL spectrum, the combination of a 300 nm SiO2 overlayer plus RTA caused a shift to lower energy of the main PL peak. This difference was attributed to a change in the shape of the CDQW structure caused by capped RTA.

scholarly journals Asymmetric double quantum wells with smoothed interfaces

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Vladimir Gavryushin
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
External Electric Field ◽  
Energy Levels ◽  
Double Quantum ◽  
Inverse Population ◽  
Double Quantum Well ◽  
The One ◽  
Interface Disorder ◽  
Asymmetric Double Quantum Wells

AbstractWe have derived and analyzed the wavefunctions and energy states for an asymmetric double quantum well (ADQW), broadened due to interdiffusion or other static interface disorder effects, within a known discreet variable representative approach for solving the one-dimensional Schrodinger equation. The main advantage of this approach is that it yields the energy eigenvalues, and the eigenvectors, in semiconductor nanostructures of different shapes as well as the strengths of the optical transitions between them. The behaviour of ADQW states for the different mutual widths of coupled wells, for the different degree of broadening, and under increasing external electric field is investigated. We have found that interface broadening effects change and shift energy levels, not monotonously, but the resonant conditions near an energy of sub-band coupling regions do not strongly distort. Also, it is shown that an external electric field may help to achieve resonant conditions for inter-sub-band inverse population by intrawell emission of LO-phonons in diffuse ADQW.

GIANT INCREASE OF THE EXCITON LIFETIME IN SEMIMAGNETIC SEMICONDUCTORS WITH DOUBLE QUANTUM WELLS IN MAGNETIC FIELD

2004 ◽  
Vol 03 (04n05) ◽  
pp. 541-547
Author(s):  
I. Yu. GOLINEY ◽  
S. B. LEV ◽  
V. I. SUGAKOV ◽  
G. V. VERTSIMAKHA
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Double Quantum ◽  
Quantum Well Structures ◽  
Indirect Exciton ◽  
Exciton Lifetime ◽  
Double Quantum Well ◽  
Single Well ◽  
Semimagnetic Semiconductors

Magnetic field dependence of the excitonic spectrum and the intensity of the optical transitions for excitons in the double quantum well heterostructures based on semimagnetic semiconductors of various compositions are studied. The calculations carried out for (Zn, Mn)Se -based double quantum well structures showed that in the weak magnetic fields, the lowest energy states are the single-well states (direct excitons) for which both the electron and the hole are predominantly localized in the same well. At some values of magnetic field, the crossing of the direct exciton with indirect exciton formed by an electron and a hole, situated predominantly in the different wells, occurs. In the magnetic field exceeding some critical value, the lowest energy level belongs to the indirect exciton. According to the estimates, the lifetime of the indirect exciton is by several orders of magnitude larger than that of a single-well exciton. The exciton lifetime depends significantly on the width and the material of the barrier between the wells.

RKKY Interaction Between Impurities in GaAs/AlAs Quantum Wells

1997 ◽  
Vol 11 (05) ◽  
pp. 195-199
Author(s):  
I. C. da Cunha Lima ◽  
L. G. Ferreira Filho ◽  
A. Troper
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Quantum Wells ◽  
Strong Electric Field ◽  
Double Quantum ◽  
Magnetic Impurities ◽  
Barrier Width ◽  
Rkky Interaction ◽  
Double Quantum Well ◽  
Fast Decrease

The RKKY interaction between two magnetic impurities in a GaAs/AlAs double quantum well under a strong electric field perpendicular to the interfaces is obtained as a function of the field strength and the barrier width. We obtain a fast decrease of the exchange with the barrier width for the impurities lying in different wells. At intermediate strengths and small barrier widths, a structure is observed in the inter-well exchange.

ELECTRONIC STRUCTURE AND BAND BENDING OF MODULATION-DOPED GaAs/AlxGa1-xAs SYMMETRIC AND ASYMMETRIC DOUBLE QUANTUM WELLS UNDER AN APPLIED ELECTRIC FIELD

2009 ◽  
Vol 16 (01) ◽  
pp. 105-110 ◽  
Author(s):  
F. UNGAN ◽  
E. KASAPOGLU ◽  
H. SARI ◽  
I. SÖKMEN
Keyword(s):  
Electric Field ◽  
Quantum Wells ◽  
Growth Direction ◽  
Double Quantum ◽  
Total Charge ◽  
Carrier Distribution ◽  
Band Bending ◽  
Mass Approximation ◽  
Double Quantum Well ◽  
And Shifts

In this study, we have calculated theoretically the effects of the electric field and doping concentration on the sub-band energies, the electron population, and total charge density in modulation-doped symmetric and asymmetric GaAs / Al 0.33 Ga 0.67 As double quantum wells. Electronic properties of the system are determined by the solving the Schrödinger and Poisson equations self-consistently in the effective-mass approximation. The application of an electric field in the growth direction of the system causes a polarization of the carrier distribution and shifts the sub-band energies, which may be used to control and modulate intensity output devices. In an asymmetric double-quantum-well structure, the effects mentioned above appear more clearly.

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