Introduction
The document addresses the challenges in electrically characterizing nanoscale wires and tubes, focusing on semiconductors and materials like Single Wall Carbon Nanotubes (SWNT). Traditional systems are inadequate for nanoscale electronics, but the Keithley Model 4200-SCS with the Zyvex S100 Nanomanipulator provides precise measurements with 5nm precision and probe tips under 20nm.

Methods and Techniques
The four-point probe technique is recommended for nanoscale measurements to avoid inaccuracies from lead and contact resistance. This method uses separate probes for current sourcing and voltage sensing, ensuring accurate resistance measurements.

Test System Configuration
The Keithley 4200-SCS and Zyvex S100 system allows automated I-V and C-V characterization of nanoscale devices, achieving a noise floor of less than 55fA rms and current measurements better than 1pA. The Keithley Interactive Test Environment (KITE) is used for test configuration and execution.

Typical Sources of Error
Errors can arise from offset voltages, thermoelectric voltages, non-ohmic contacts, device heating, and contaminated probes. Mitigation strategies include using consistent materials, ensuring proper contact materials, and maintaining clean probe tips.

Test System Safety
Safety precautions are essential due to potential hazardous voltage and power levels. Recommendations include designing test fixtures to prevent operator contact with hazardous circuits, using double insulation, and employing fail-safe interlock switches.

Training and Safety
Proper training is crucial for all system users to understand potential hazards and protect themselves. The responsibility for safety lies with the system designers, integrators, and installers.

Further Reading
For more information on resistance measurements and typical sources of error, refer to Keithley’s Low Level Measurements handbook.

Conclusion
The Keithley 4200-SCS Semiconductor Characterization System, combined with the Zyvex Test System, is effective for I-V characterization of nanoscale components, featuring four-point probe capability, 1pA accuracy, and 5nm precision movement.

Acknowledgements
Keithley Instruments acknowledges Phil Foster and Jeff Hochberg of the Zyvex Corporation for their contributions.

Contact Information
Keithley Instruments, Inc., 28775 Aurora Road, Cleveland, Ohio 44139, Phone: 440-248-0400, Fax: 440-248-6168, Toll-Free: 1-888-KEITHLEY (534-8453), Website: www.keithley.com

Note
Specifications are subject to change without notice. All trademarks are the property of their respective companies.