Conductance through chains of Ge/Si quantum dots: crossover from one-dimensional to quasi-one-dimensional hopping
N. P. Stepina+, V. V. Valkovskii+*, Y. M. Galperin×°, Zh. V. Smagina+, A. V. Dvurechenskii+*
+Rzhanov Institute of Semiconductor Physics SB of the RAS, 630090 Novosibirsk, Russia
*Novosibirsk State University, 630090 Novosibirsk, Russia
×Department of Physics, University of Oslo, PO Box 1048 Blindern, 0316 Oslo, Norway
°Ioffe Physical Technical Institute, 194021 St. Petersburg, Russia
Parallel chains of germanium quantum dots were grown on a patterned
silicon (100) substrate prepared by the combination of nanoimprint lithography
and ion irradiation. Strong anisotropy of the conductance between the
direction of the chains and the perpendicular one was observed; the
current-voltage curves being essentially superlinear.
At low bias voltage dependence of
the conductance obeys the Arrhenius law indicating one-dimensional (1D) hopping.
With increase of the bias this dependence crosses over to
explained by a quasi-1D transport involving hopping between
nearest neighboring chains.