QIT-SSL Seminar Series 2007 No. 2

Date: 21 May (Monday), 2007
Time: 2:00am-3:00pm
Venue: Physics Resource Room (Blk S13 #2-16)

Speaker: Dr.Chen Wei
Title: Assembling linear fullerene arrays for quantum information processing

Abstract:
Creation of well-ordered functional molecular arrays at the nanometer scale is one of the key issues in the development for future molecular- or nano-electronic devices, solid-state quantum computation, single-electron devices, and biosensors. In particular, in proposed fullerene-based quantum computers, two-dimensional fullerene arrays with long range ordering are the ideal building units for the fault-tolerant quantum computers. By manipulating the subtle balance between intermolecular, intramolecular and interfacial interactions, we demonstrate the formation of various well-ordered C 60 superstructures with tunable periodicity and symmetry, including C 60 dot arrays, C 60 -rail arrays and C 60 -pair arrays on a-sexithiophene (6T) bilayer on Ag(111), single-chain and double-chain C 60 arrays on 6T monolayer on Ag(111), “Zigzag” C 60 arrays on 6T monolayer on HOPG, C 60 supergrating and square-nanomesh on p -sexiphenyl (6P) bilayer on Ag(111). It is found that that the formation of the tunable C 60 molecular arrays arises from the delicate balance between the homo-intermolecular (C 60 -C 60 and 6T-6T or 6P-6P, van-der-Waals forces), hetero-intermolecular (C 60 -6T or C 60 -6P, charge transfer) and molecule-substrate [C 60 -Ag(111) and 6T-Ag(111), 6T-HOPG or 6P-Ag(111)] interfacial interactions under different experimental conditions, which can be simply adjusted by choosing appropriate C 60 and 6T or 6P coverages and post annealing temperature. Our results suggest that controlling the intermixed phases of binary or multicomponent molecular systems represents a simple and effective method for the construction of highly ordered functional molecular nanostructure arrays , and offers a versatile route towards the fabrication of novel molecular interconnects and devices. In particular, it could be a possible nanofabrication route towards a fullerene-based quantum computer.