Zero dimensional resonant tunneling through single donor states

✍ Scribed by M.W. Dellow; C.J.G.M. Langerak; P.H. Beton; T.J. Foster; P.C. Main; L. Eaves; M. Henini; S.P. Beaumont; C.D.W. Wilkinson

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 325 KB
• Volume: 11
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1016/0749-6036(92)90240-6

✦ Synopsis

We have observed remarkable new structure in the source-drain I(V) characteristics of a symmetric double barrier resonant tunneling device in which the cross sectional area may be varied from = 1 /cm2 to -0.1 jrm2 by applying a voltage to a gate.

In the source-drain voltage range close to, but slightly below, the threshold for current flow, peaks are observed with a peak value of -20 pA, and peak/valley ratio up to 10/l. The structure in I(V) is independent of temperature between 35 mK and 10 K, and of gate voltage between 0 and -2 V. The first peak in I(V) in each polarity is unaffected by a magnetic field applied parallel to the current flow for fields up to 6 T. This structure cannot be explained by lateral quantisation or Coulomb blockade arising from the confinement. We propose that it is due to resonant tunneling between zero-dimensional states formed in the active region by the Coulombic potential of a single ionised donor, combined with the barrier potential.