  Graphene nanoribbons and constrictions are envisaged as fundamental
components of future carbon-based nanoelectronic and spintronic devices. At
nanoscale, electronic effects in these devices depend heavily on the dimensions
of the active channel and the nature of edges. Hence, controlling both these
parameters is crucial to understand the physics in such systems. This review is
about the recent progress in the fabrication of graphene nanoribbons and
constrictions in terms of low temperature quantum transport. In particular,
recent advancements using encapsulated graphene allowing for quantized
conductance and future experiments towards exploring spin effects in these
devices are presented. The influence of charge carrier inhomogeneity and the
important length scales which play a crucial role for transport in high quality
samples are also discussed.
