Electronic transport through a junction formed between silicon (Si), a monolayer of alkyl chains (C14H29) self-assembled on Si, and a metal (M) is dominated by thermionic emission above the semiconductor barrier and tunneling through the insulating molecular layer . This team of PCCM and Weizmann investigators recently showed  that exposing the alkyl monolayers to electron irradiation induces new states between the occupied and unoccupied states of the pristine alkyl chain, evidently through the creation of C=C double bonds and C-C crosslinks since the overall layer density is unaffected. These states strongly affect electronic transport through the monolayer, suggesting a way to significantly extend the use of monolayers in molecular electronics.
J-V curves for n-Si-C14H29/Hg junctions, (red) non-irradiated monolayer, (black) freshly irradiated, (blue) irradiated monolayer remeasured after 1 week. Bias is applied to the Si, and the Hg drop is grounded.