Caltech collaboration for DNA-organized Nanoelectronics The Caltech DNA- nanoelectronics team

State of the art, DNA self- assembly 1, DNA origami

State of the art DNA self- assembly 2, DNA tiles, tubes and crystals

State of the art DNA self- assembly 3, algorithmic + combination

Challenges for DNA organized nanoelectronics 1A Si/ SiO 2 Pd + +

Challenges for DNA organized nanoelectronics 1B To make nanostructures more rigid and to avoid aggregation origami-ribbon hybrids are used. crossbar red tubeblue tubes 50 nm MOSFET geometry ChannelGate red and blue hooks

Challenges for DNA organized nanoelectronics 1C Over 30% of tubes are within 10 degrees of the desired orientation Characterization of DNA self-assembled CNT FET I SD V SD VgVg ab I SD Orientation of SWNT % 2% 76% Red side (-1) Unknown (0) Blue side (1) Frequency Angle

Challenges for DNA organized nanoelectronics 2

Challenges for DNA organized nanoelectronics 3,4

Challenges for DNA organized nanoelectronics 4,5

Rothemund’s Aims

Bridging nano and micro

Divergent wires

Winfree’s Aims

From counters to demultiplexers and squares

Self-assembled memory circuit

Bockrath'sAims: To self-assemble and characterize circuits of more than one carbon-nanotube based device to create elementary logic gates and memory elements. To use short length-sorted carbon nanotubes to increase the yield of existing devices. (Many problems arise from very long tubes acting as bridges between multiple origami). To self-assemble novel devices to explore transport physics in nanostructures. Bockrath’s Aims

Rationally Engineered Logic gates and Memory Elements Utilizing Multiple Nanotubes VsVs V in V out VsVs VsVs VsVs V in1 V out V in2 Inverter SRAM NOR Nanotube assemblySchematic circuit diagram

B V I Novel Devices Probing Transport Physics in Nanostructures: Phase Coherence in Strongly-Interacting Electron Systems Nanotubes act as a “which path?” interferometer enabling the study of phase coherent transport in Nanotube-based Luttinger liquids via a transport experiment. The setup is analogous to a double slit experiment in optics. The magnetic field B tunes the phase by the Ahoronov-Bohm effect. Tubes must be closer together than the phase coherence length in the electrodes, which is readily obtainable using DNA based self-assembly. Tunable separation with desired values ~5-20 nm DNA origami template for parallel nanotubes Interferometer device source drain Many possibilities exist for making novel devices. Novel Devices Probing Transport physics

Goddard’s Aims

Size of molecules quantum descriptions necessary. Quantum chemistry of molecule(s) + nanotube -> charge flow & bonding -> geometry & energy spectrum of the entire system. Organo-metallic interface mechanics and transport. Need to treat molecule as finite and nanotubes as semi-infinite electrodes. Escape currents (through organic insulator layer). Conformation effects on electronic transport. Effect of finite bias. IV characteristic of self-assembled CNT-based transistor junctions. HOMO LUMO I CNT DNA Organic molecule CNT V DNA-origami CNT-based Transistor Junctions Theory and Modeling to Describe…

Multiscale Methodology: 1 st -principles I-V validated by rotaxane modeling Density-functional theory (Hohenberg-Kohn-Sham) Ballistic transport theory (Landauer, Buttiker) T(E,V) contact widening self-energy Green’s ftn. Formalism (Fisher-Lee) transmission electro-chemical potential conductance current Molecular Mechanics Dynamics Molecular Mechanics Dynamics geometry dI/dV e.g. Rotaxane switch   1 m 2

Further validation: bi-phenyl-dithiol modeling Au (111) T(E) I(V) molecule contact

Relevance to ONR

Budget Budget for 4 years, $2.6 million including: PI: Paul Rothemund: $200K/yr for Senior Research Associate salary and materials Co-PI: Mark Bockrath $100K/yr for 1 graduate student and materials Co-PI: Bill Goddard $100K/yr for 1 graduate student and materials Co-PI: Erik Winfree $100K/yr for 1 graduate student and materials Equipment $150K/yr including plasma etcher/cleaner ($20K), wafer-scale Atomic Force Microscope ($200K) temperature-controlled dynamic light scattering ($50K).