6533b827fe1ef96bd1285b59
RESEARCH PRODUCT
Type II narrow double barrier quantum well structures : Γ-X coupling and interface effects
Jean MassiesB. ChastaingtGérard NeuJuan P. Martínez-pastorMassimo GurioliChristiane DeparisMarcello Coloccisubject
PhotoluminescenceCondensed matter physicsCoupling parameterChemistryExciton[PHYS.HIST]Physics [physics]/Physics archivesMonolayerGeneral Physics and AstronomyMolecular physicsQuantumVicinalExcitationQuantum welldescription
Photoluminescence (PL), PL excitation and time resolved PL experiments have been performed on Al0.42Ga0.58As/AlAs/GaAs symmetric double barrier quantum wells (DBQW) with only one or two AlAs monolayers constituting the intermediate barriers. In agreement with the envelope function predictions we show that such DBQW's undergo a type I - type II transition when the GaAs thickness is reduced below 7 and 5 monolayers for 2 and 1 AlAs molecular planes respectively. In type II configuration the PL decay time is found to be strongly dependent on the energy difference between AlAs Xz - and GaAs Γ - electron confined states and the coupling parameter of the Γ and Xz valleys can be deduced (4.2 meV on average). Similar experiments on DBQW's grown on 2° off (001) vicinal surfaces show that the exciton lifetime remains close to that of nominal samples. Considering also former results obtained in type II GaAs/AlAs superlattices, it is concluded that the Γ-X mixing potential in quantum structures is intrinsically linked to the AlAs/GaAs interface.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 1993-10-01 |