Structural and electronic characterization of single-wall nanotube DNA hybrids Lolita Rotkina, Stacy E. Snyder, Slava V. Rotkin Physics Department & Center for Advanced Materials and Nanotechnology Lehigh University

Tight-binding results Self-consistent solution for the charge density of semiconductor [7,0] zigzag NT under DNA wrap perturbation

Tight-binding results Self-consistent solution for the charge density of semiconductor [7,0] zigzag NT under DNA wrap perturbation Polarization interaction: for [7,0] NT and {6:1 | 4e} wrap the cohesion energy due to the NT pi-e-system polarization de ~ 0.47 eV/b.p. interaction with the image charge overestimates C.E. image charge for semiconductor

Randomize DNA potential

Scaling results: Gaps in S- M-NTs

Scaling results: Gaps in S- M-NTs

Scaling results: Gaps in S- M-NTs

Novel STM-TEM facility _____________

STM-TEM Nanofactory stage To be installed inside JEOL 2200FS FEG-TEM STM-TEM Nanofactory stage by Gatan All images courtesy Gatan (unless author specified)

STM-TEM Nanofactory stage Nanofactory controller Side entry TEM sample holder is equipped with a full power STM TEM-STM Stage Computerized control

STM-TEM Nanofactory stage Inertial slider-driven coarse movement Piezo-driven fine movement Interchangeable sample holders

STM-TEM Nanofactory stage < 1 mm – 1 mm Inertial slider-driven coarse movement Sample holder Piezo-driven fine movement < 0,1 Å – 2,5 mm < 1 Å – 20 mm

In-situ Characterization STM -TEM Si whiskers

Characterization (1) Novel characterization technique: transport-STM-TEM combined tool spring ring contact pads and mirror pads sample holder membrane bottom view

Characterization (1) Novel characterization technique: transport-STM-TEM combined tool

Characterization (1) Novel characterization technique: transport-STM-TEM combined tool

Characterization (1) Novel characterization technique: transport-STM-TEM combined tool 5 nm 20 nm 20 nm HR-TEM Cs aberration corrected dedicated TEM/STEM (Kiely)

Charge Trapping and Memory Effects _____________

Characterization (2) Liquid crystal placement for FET/sensor fabrication (Jagota) Novel femtosecond characterization technique: fast photoelectric response (Biaggio, COT, Lehigh)

Characterization (2) Keithley Semiconductor Characterization Station 4200 with pA preamplifier. Custom made low-current low-noise photo-electric probe station (Biaggio, Rotkin)

Photoresponse of Polymer-NT FET sample 3 Id/Vd, mA/V 1.14 1.15 1.16 1.17 1.18 -1.5 V -1.0 V -0.5 V 1.5 V 1.0 V Vd = 0.5 V 25 50 75 100 125 150 175 t, sec Photoconductance Id/Vd vs time of the light pulse. Amplitude is independent of Vd (and Vg)

Photoresponse of Polymer-NT FET sample 3 1 2 3 4 5 Qg, nC t, sec Ig /Vg, nA/V 1 2 3 4 5 6 7 t, sec 50 100 150 200 Total photocurrent pulse = trapped charge

Photoresponse of Polymer-NT FET Id/Vd / (Idmax/Vdmax), a.u. sample 3 sample 6 1 1.005 1.01 1.015 1.02 1.025 1.03 20 40 60 80 100 120 140 t, sec Photoresponse is similar for two different polymer substrates.

Hysteresis in SWNT-array Transistors Experiment: Laminated Device, CVD Tubes decreasing scan rate Courtesy J.Rogers Robert-Peillard, Rotkin, 2005

Single NT FET insulator Physics of current hysteresis in NT FETs: Gate voltage controls the charge of the channel In addition to the charge stored in the gate (gate capacitance), strong electric field generates charges at the interfaces (add.capacitances) This shifts the threshold voltage (and changes mobility) The field is self-consistent with the charge source @ ground drain @ Vd 1D channel insulator gate @ Vg