Room temperature (RT) I-V characteristics of epitaxially group Si/SiGe/Si p
(+)/i/n(+) Esaki diodes are presented. The incorporation of Ge within the i
ntrinsic (i) zone gives rise to an increased peak current density (j(P) = 3
kA/cm(2)) and peak-to-valley current ratio (PVCR) compared to pure Si struc
tures (j(P) = 80A/cm(2)). A detailed investigation and optimisation of post
-growth annealing has demonstrated a record PVCR of 4.2 for Si based Esaki
diodes.