| Field Effect Transistors using Carbon Nanotubes |
| Slide 2 |
| How a NTFET Works |
| How a NTFET Works |
| How a NTFET Works |
| Nanotube FET transistor |
| Effect of charge transfer on the device electronics |
| Slide 8 |
| Metallic vs. Semiconducting |
| Metallic Tubes are the Enemy |
| Deposition Techniques |
| Want: Uniform Film of individually separated NT’s | |||
| Direct Deposition | |||
| Drop Casting -- Flocculation due to Van der Waals | |||
| between tubes limits uniformity. | |||
| Spin Coating – work in progress | |||
| Langmuir-Blodgett/Quasi-Langmuir-Blodgett | |||
| Separate Tubes using Solubilization Agents | |||
| Starch/Enzymes | |||
| PmPV | |||
| Quasi-Langmuir-Blodgett Film |
| Quasi-Langmuir-Blodgett Film |
| Quasi-Langmuir-Blodgett Film |
| Quasi-Langmuir-Blodgett Film |
| Why 10:1 solvent mixture? |
| Ortho-xylene:Dichlorobenzene solvent mixture used for 3 reasons | ||
| 1) High nanotube solubility ≈ 15 mg/L | ||
| 2) Specific Gravity < 1 (so rafts can float) | ||
| 3) Immiscibile in water | ||
| Quasi-Langmuir-Blodgett Film |
| Does water Immersion affect Films? |
| Quasi-LB Film: Are They Uniform? |
| Device Fabrication |
| Measurement Setup |
| Output (Vg ) ±100 V quasi-AC | |
| Sawtooth Waveform. | |
| Output bias voltage (100mV) | |
| across SD, and measure Isd | |
| Measure Voltage across Rprot to get Ileakage | |
| Transistor Characteristics |
| Transistor Characteristics |
| Transistor Characteristics |
| Vsd vs Isd |
| Transistor Characteristics |
| Exponentially Better with Film thinness |
| Calculation of Mobility |
| Quadratic Model of MOSFET: | |||
| ISD = (μCoxW)[(VGS – VT)VDS – VDS2/2] for VDS << VGS – VT | |||
| Slope of IVg curve = μCoxWVDS | |||
| Plugging in the numbers yields mobility of 0.9 cm2/V*s | |||
| Mobility's: Single Carbon NT = 105 | |||
| Silicon = 102-103 | |||
| NT Network = 101 | |||
| Organic Semiconductor = 10-4 - 10-1 | |||
| High Mobility means device can operate at Higher frequency!!! | |||
| Liquid Gating |
| Nanotube Reflux in Nitric Acid |
| Slide 31 |
| Did the Reflux Work? |
| Future Work |
| Improve Device Characteristics | ||
| Thinner Films | ||
| More Dispersed Tubes | ||
| Separate Semiconducting and Metallic Tubes | ||
| Mobility vs. applied pressure | ||
| Improve Probe Station | ||
| True AC Setup | ||
| Gold Pogo Pin probe/Micrometer positioner | ||
| Temperature/Humidity Control Chamber | ||
| Characteristics vs. Network Density | ||
| Photo-lithographic Mask for micro scale geometries | ||
| Study 2-D Percolation problem of random array of semiconducting rods | ||
| E-Beam Lithography for nano scale geometries | ||
| Protein detection | ||
| Conclusion |
| Created NT network transistor using room temperature fabrication process | |
| Film too thick to get good characteristics. |
| Thanks |
| The Gruner Group: Peter Armitage, M. Briman, Erika Artukovic, Liangbing Hu, George Gruner | |
| The Chemists: Erik Richman, Will Molenkamp (Tolbert); Matt Spotnitz (Kaner). | |
| Steve Franz (Nanolab). | |
| MCTP |