Physics of Resonant Tunnelling
F.W. Sheard and T.M. Fromhold
Department of Physics, University of Nottingham, Nottingham NG7 2RD, England
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A description is given of resonant tunnelling processes in double-barrier semiconductor heterostructures from the point of view of sequential theory. If a magnetic field is applied in the plane of the barrier interfaces, the energy and transverse momentum of the electrons injected into the quantum well through the emitter tunnel barrier can be varied independently by changing the applied voltage and magnetic field. This technique can be used to probe the energy and momentum spectrum of the subband states in a quantum well. In n-type wide-well structures, a detailed interpretation of magneto-oscillations in the tunnel current has been given in terms of semiclassical orbits of electrons in the well. In p-type structures with narrow wells, the dispersion curves of hole subbands, which are complicated by the strong mixing of light hole and heavy hole states, have been directly studied. Resonant tunnelling into the bound state of single donor atoms in a quantum well has recently been observed. The magnetic field dependence of the tunnel current then gives a measure of the transverse momentum distribution and hence lateral extent of the donor wave function.
DOI: 10.12693/APhysPolA.82.523
PACS numbers: 73.20.Dx