  We study quantum diffusion of wavepackets in one-dimensional random binary
subject to an applied electric field. We consider three different cases:
Periodic, random, and random dimer (paired) lattices. We analyze the spatial
extent of electronic wavepackets by means of the time-dependent inverse
participatio ratio. We show that the delocalized states recently found in
random dimer lattices become spatially localized under the action of the
applied field (dynamical localization) but wavepackets are much less localized
than in purely random lattices. We conclude that the resonant tunneling effects
causing delocalization play an important role even in the presence of the
electric field.
