Quantum-Size-Induced Electronic Transitions in Quantum Dots: Indirect Band-Gap GaAs

Journal Article · Tue Jan 01 04:00:00 EST 2008 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PhysRevB.78.035306· OSTI ID:950720

Luo, k J.-W.; Franceschetti, A; Zunger, A

We discuss the physical origin of the previously predicted quantum-size-induced electronic transitions in spherical GaAs quantum dots. By using atomistic pseudopotential calculations for freestanding GaAs dots and for GaAs dots embedded in an AlGaAs matrix, we are able to distinguish two types of direct/indirect transitions: (i) in freestanding GaAs dots, the conduction-band minimum changes from {Lambda}-like to X-like as the radius of the dot is reduced below 1.6 nm, leading to a direct/indirect transition in reciprocal space. (ii) In GaAs dots embedded in AlAs, the conduction-band minimum changes from dot localized to barrier localized as the radius of the dot is reduced below 4.2 nm, corresponding to a direct-to-indirect transition in real space.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO.
• Sponsoring Organization: USDOE
• DOE Contract Number: AC36-99GO10337
• OSTI ID: 950720
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 3, 2008 Vol. 78
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
77 NANOSCIENCE AND NANOTECHNOLOGY
Basic Sciences
ORIGIN
PHYSICS
QUANTUM DOTS
Solid State Theory