Structural and electrical properties of Flip Chip Laminated metal-molecule-silicon structures modifying molecular backbone and atomic tether
Mariona Coll Bau, Nadine Gergel-Hackett, Curt A. Richter, Christina Hacker
The formation of electrical contacts on organic molecules preserving their integrity and using a scalable technique is a key step toward the fabrication of molecular electronic devices. Here we study the structural and electrical properties of metal-monolayer-silicon junctions fabricated by the novel, low cost and non-destructive approach Flip Chip Lamination (FCL). Molecular backbone and molecule-electrode interface have been systematically modified in the molecular junction. Molecular junctions formed from aliphatic alkyl-backbone MHE (CH=CH-(CH2)15-SH) and DDT (SH-(CH2)10-SH), and the p-conjugated TPDT (SH-(C5H6)3-SH) have been investigated by polarized backside-reflection absorption infrared spectroscopy (pb-RAIRS) and I-V measurements. This work extends our early study of FCL molecular junctions using carboxy-terminated alkanethiols MHA (COOH-(CH2)15-SH). Pb-RAIRS characterization indicates that overall the confined organic monolayers maintain the structure of the free standing monolayers. Small changes in molecular backbone conformation are attributed to lamination conditions and the anchor of the molecular terminal group to silicon. Current - voltage measurements support the presence of the organic monolayer with no trace of degradation and show saturated alkyl monolayers can be distinguished from p-conjugated. Transition Voltage Spectroscopy is used to evaluate the effective barrier to charge transport across the FCL molecular junctions and minimal changes are observed for different molecule-silicon linkage. FCL is a promising technique to form molecular electronic junctions allowing detailed studies of monolayer properties. Also, it can be extended to different metals and bottom substrates, patterned metal, a great variety of molecular layers, organic crystals, and nanowires.
Coll Bau, M.
, Gergel-Hackett, N.
, Richter, C.
and Hacker, C.
Structural and electrical properties of Flip Chip Laminated metal-molecule-silicon structures modifying molecular backbone and atomic tether, ACS Nano, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906090
(Accessed December 9, 2023)