  The inclusion of heavy neutral leptons (right-handed neutrinos) to the
Standard Model (SM) particle content is one of the best motivated ways to
account for the observed neutrino masses and flavor mixing. The modification of
the charged and neutral currents from active-sterile mixing of the neutral
leptons can provide novel signatures which can be tested at the future collider
experiments. In this article, we explore the discovery prospect of a very heavy
right handed neutrino to probe such extensions at the future collider
experiments like Large Hadron electron Collider (LHeC) and liner collider. We
consider the production of the heavy neutrino via the $t$ and $s$-channel
processes and its subsequent decays into the semi-leptonic final states. We
specifically focus on the scenario where the gauge boson produced from heavy
neutrino decay is highly boosted, leading to a fat-jet. We study the bounds on
the sterile neutrino properties from several past experiments and compare with
our results.
