Oral Exam Announcement - Alex Neuhausen

Stanford University PhD Oral Defense - Department of Electrical Engineering
Date: September 26, 2011 (Monday)
Time: 1:00 PM (Refreshments at 12:45 PM)
Location: McCullough 335
Title: Molecular Junctions of Self-Assembled Monolayers with Universal Soft Contacts 

Abstract: 

As transistor scaling following Moore's Law faces mounting obstacles from device leakage and heat dissipation, numerous disruptive "post-silicon" technologies are being explored. Devices consisting of a single or few organic molecules have been proposed as extremely scalable, low-power logic and memory elements. The diversity and consistency of molecules that may be obtained through chemical synthesis has resulted in numerous exciting device proposals. However, in the many studies of transport through molecular systems that have been presented in the literature, the difficulty in establishing contacts to a desired molecular system has arisen as a complication. There is an emerging consensus that the ideal molecular device geometry should consist of a self-assembled monolayer (SAM) sandwiched between two electrodes to average out molecule-contact variations and ensure consistent behavior with scaling.

 

This talk will begin with a discussion of the general characteristics of a scalable molecular device, and then briefly review recent device designs demonstrated in the literature, with an emphasis on the limitations of the various contact materials and deposition methods. A novel, scalable, high-yield molecular junction incorporating an isolating dielectric layer and a soft polymer top contact will then be presented. Studies of transport through alkanethiol SAMs with a variety of terminations formed on gold substrates will be presented. Models explaining the molecular length-decay and unique temperature dependence behavior will be demonstrated.  Studies of devices incorporating platinum and silver substrates will be presented to provide insight into the packing behavior of the SAM. The limitations of devices with soft contacts will be explored with the presentation of studies of conjugated molecular systems and molecules with redox-active organometallic terminal groups. The demonstration of scalable, high-yield molecular junctions is an important step in the development of computing devices beyond Moore's Law.