  We study single-electron tunneling (SET) characteristics in crystalline
PbS/InP junctions, that exhibit single-electron Coulomb-blockade staircases
along with memory and memory-fading behaviors. This gives rise to both
short-term and long-term plasticities as well as a convenient non-linear
response, making this structure attractive for neuromorphic computing
applications. For further insights into this prospect, we predict typical
behaviors relevant to the field, obtained by an extrapolation of experimental
data in the SET framework. The estimated minimum energy required for a synaptic
operation is in the order of 1 fJ, while the maximum frequency of operation can
reach the MHz range.
