953 research outputs found
Theory of electrons, holes and excitons in GaAs polytype quantum dots
Single and multi-band (Burt-Foreman) k.p Hamiltonians for GaAs crystal phase
quantum dots are developed and used to assess ongoing experimental activity on
the role of such factors as quantum confinement, spontaneous polarization,
valence band mixing and exciton Coulomb interaction. Spontaneous polarization
is found to be a dominating term. Together with the control of dot thickness
[Vainorious Nano Lett. 15, 2652 (2015)] it enables wide exciton wavelength and
lifetime tunability. Several new phenomena are predicted for small diameter
dots [Loitsch et al. Adv. Mater. 27, 2195 (2015)], including non-heavy hole
ground state, strong hole spin admixture and a type-II to type-I exciton
transition, which can be used to improve the absorption strength and reduce the
radiative lifetime of GaAs polytypes
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