Single-electron tunneling and Coulomb charging effects in ultrasmall double-barrier heterostructures
1994; Elsevier BV; Volume: 37; Issue: 4-6 Linguagem: Inglês
10.1016/0038-1101(94)90300-x
ISSN1879-2405
AutoresM. Tewordt, V.J. Law, J. T. Nicholls, L. Martı́n-Moreno, D. A. Ritchie, Michael J. Kelly, M. Pepper, J. E. F. Frost, R. Newbury, G. A. C. Jones,
Tópico(s)Semiconductor Quantum Structures and Devices
ResumoAn extensive study of charge transport through submicron-diameter double barrier heterostructure diodes is reported. The occupation of the quantum well with single electrons, starting from zero, is observed in the form of sharp steps in the current-voltage characteristics. The magnitude of the current steps can be controlled by changing the barrier thicknesses and thus their transparency for tunneling electrons. The plateau width of the current steps is related to the energies of the electron states in the quantum well that are affected by the lateral quantum confinement, and by Coulomb charging effects. Diameter dependent studies of the tunneling current suggest that the lateral quantum confinement can result from the surface depletion potential, potential fluctuations, or single impurities. High magnetic field studies confirm this conclusion. The contribution of the Coulomb charging energy is investigated by using an asymmetric double barrier profile. It is shown that tunneling through submicron-diameter double barrier heterostructures provides valuable insight into the electronic properties of quantum boxes containing a few electrons.
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