This paper reports on the experimental investigation of metal-insulator-metal (MIM) diodes based on alkyltrichlorosilane self-assembled monolayers (SAMs) with different alkyl chain lengths. The insulating SAM is sandwiched between two metal contacts, Pt and Ti, with different work functions. The electronic properties of the MIM diodes can be tuned by controlling the alkyl chain length of the SAMs to address different constraints in high speed electronics applications. Data fitting of the tunneling current through the MIM junctions using the Fowler-Nordheim model suggests that the device operation is influenced by the barrier heights of the diodes and thicknesses of the SAMs. The current-voltage characteristics achieved in MIM diodes based on alkyltrichlorosilane SAMs make them promising candidates for high speed electronics applications.