Advances in molecular scale electronics: Synthesis and testing of nanoscale wires and devices
Rawlett, Adam Madison
Tour, James M.
Doctor of Philosophy
Chapter 1 discusses advances in molecular scale electronics. With the miniaturization of transistors on silicon semiconductor chips comes faster processing speeds and more powerful computational power; however, certain size constraints on today's semiconductor industry will soon be realized. Therefore, a new method of computer architecture must be developed. The use of a discrete, highly conjugated organic molecule as a molecular scale wire to conduct an electric current has been demonstrated. We have developed molecular scale gates, from organic molecules, that can be altered "on" and "off" with the use of an electric field. Additionally, we have synthesized and tested nanoscale devices that exhibit negative differential resistance with a valley to peak ratio of over 1000:1 that is 10 times that of current solid-state devices and shown long lasting random access memory. The use of these molecular scale wires and devices should allow us to overcome the miniaturization barrier. Chapter 2 describes a simple bench-top gravity column chromatography method for the purification of C60, C70, and the higher fullerenes < C100. The stationary phase is based on poly(dibromostyrene)/divinylbenzene and the eluent is chlorobenzene. This new stationary phase (1) uses an inexpensive monomer that can be easily polymerized by standard suspension techniques, (2) permits the use of potent fullerene solvents, and (3) can be reused without additional preparation. Chapter 3 discusses the use of phenylene ethynylene oligomers as self assembled monolayer negative tone resist for the manufacture of even smaller semiconductor chips. With current methods of silicon etching with polymer resists, devices with sub-25 run feature size are not obtainable. We have prepared the first self-assembled monolayer that upon irradiation acts as a negative tone resist. In addition, we have synthesized a phenylene-ethynylene substituted trichlorosilane that should crosslink with exposure to irradiation to be a superior resist material. We are currently in the process of evaluating what functionalities are necessary to form negative tone resists at lower doses of energy. This will allow the fabrication of device feature sizes below 8 nm. Chapters 4, 5, and 6 discuss the great utility of substituted phenylene ethynylenes in the areas of cluster and surface binding study, STM patterning, and organic LEDs.
Organic chemistry; Electronics; Electrical engineering