A novel and simple method of fabrication of mesoscopic honeycomb-shaped net
works was applied in order to decrease the dimension of the 2-D gas with el
ectron density of approximately 1 x 10(12) cm(-2) in the initial GaAs/AlGaA
s delta -doped heterostructures. The characteristic dimensions of the size
of hexagonal cell and the thickness of bonds of the network were approximat
ely 500 and 70 nm, respectively. Magnetoresistance in pulsed magnetic field
s up to 34 T, current-voltage (I(V)) curves and the temperature dependence
of resistance in the mesoscopic networks were measured at temperatures 1.9-
300 K. At B = 0, the behaviour of the resistance is typical of a two-dimens
ional insulator. Below approximately 20 K, the data follows the Mott variab
le-range-hopping mechanism for 2-D. The observed negative magnetoresistance
at low magnetic fields was related to quantum interference in the variable
range hopping. At magnetic fields higher than approximately 5 T, the magne
toresistance is positive and saturates at fields B > 12T. (C) 2001 Elsevier
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