Coupling of electron states in the InAs/GaAs quantum dot molecule

Journal Article · Wed Mar 15 04:00:00 EST 2006 · Semiconductors

DOI:https://doi.org/10.1134/S1063782606030146· OSTI ID:21088578

Zhukov, A E; Vasil'ev, A P; Semenova, E S; Mikhrin, V S; Cirlin, G E; Musikhin, Yu G ^[1]

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1. Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

Deep level transient spectroscopy (DLTS) is used to study electron emission from the states in the system of vertically correlated InAs quantum dots in the p-n InAs/GaAs heterostructures, in relation to the thickness of the GaAs spacer between the two layers of InAs quantum dots and to the reverse-bias voltage. It is established that, with the 100 A GaAs spacer, the InAs/GaAs heterostructure manifests itself as a system of uncoupled quantum dots. The DLTS spectra of such structures exhibit two peaks that are defined by the ground state and the excited state of an individual quantum dot, with energy levels slightly shifted (by 1-2 eV), due to the Stark effect. For the InAs/GaAs heterostructure with two layers of InAs quantum dots separated by the 40 A GaAs spacer, it is found that the quantum dots are in the molecule-type phase. Hybridization of the electron states of two closely located quantum dots results in the splitting of the levels into bonding and antibonding levels corresponding to the electron ground states and excited states of the 1s{sup +}, 1s{sup -}, 2p{sup +}, 2p{sup -}, and 3d{sup +} types. These states manifest themselves as five peaks in the DLTS spectra. For these quantum states, a large Stark shift of energy levels (10-40 meV) and crossing of the dependences of the energy on the electric field are observed. The structures with vertically correlated quantum dots are grown by molecular beam epitaxy, with self-assembling effects.

• OSTI ID: 21088578
• Journal Information: Semiconductors, Journal Name: Semiconductors Journal Issue: 3 Vol. 40; ISSN SMICES; ISSN 1063-7826
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DEEP LEVEL TRANSIENT SPECTROSCOPY
ELECTRON EMISSION
EV RANGE 01-10
EXCITED STATES
GALLIUM ARSENIDES
GROUND STATES
INDIUM ARSENIDES
LAYERS
MEV RANGE 10-100
MOLECULAR BEAM EPITAXY
QUANTUM DOTS
STARK EFFECT