Charge-carriers propagating in superlattices exhibit the related phenomena
known as negative differential conductivity and Bloch oscillation.
This behaviour may be utilised for the generation of tunable
electromagnetic radiation. In this work, the dependence of the drift velocity
and displacement of charge-carriers on external, applied electric
fields is investigated. The theory is extended to incorporate a different
miniband structure, with the aim of modelling a superlattice made from
graphene. I predict that, for a chosen set of electric field parameters,
a semiconductor superlattice will emit radiation in the terahertz range.
I create an original mathematical framework within which to calculate
the charge-carrier behaviour in a triangular miniband structure, while
incorporating an arbitrary variable to account for the effects of corrugation
or disorder, and predict the appearance of conductivity multistability.
This may be of interest to further work done on the use of graphene
for superlattice device construction.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.