IEEE 1650-2005 pdf download IEEE Standard Test Methods for Measurement of Electrical Properties of Carbon Nanotubes
1. Overview
1.1 Scope
This standard provides methods for the electrical characterization of carbon nanotubes (CNTs). Themethods will be independent of processing routes used to fabricate the CNTs.
1.2 Purpose
There is currently no defined standard for the electrical characterization of CNTs and the mcans ofreporting performance and other data, Without openly defined standard test methods, the acceptance anddiffusion of CNT technology will be severely impeded. This standard is intended to provide and suggestprocedures for characterization and reporting of data. These methods will enable the creation of a sugeestedreporting standard that will be used by research through manufacturing as the technology is developedMoreover, the standards will recommend the necessary tools and procedures for validation.
1.3 Electrical characterization overview
1.3.1 Testing apparatus
Testing shall be performed using an clectronic devicc test system with mcasurement sensitivity sufficicnt togivc a measurement resolution of at lcast +01% (minimum sensitivity at or better than three ordcrs ofmagnitude bclow expected signal levcl). For examplc, the smallest current through a CNT can be on thcorder of 1 pA (10-2 A) or smaller. Therefore, in this case the instrument shall have a resolution of 100 aA(10-‘ A) or smaller, Additionally, due to the various impedances encountered in nanoscale measurements,the input imnedance of all clements of the test system shall be at least three orders of magnitudc grcatcrthan the highest impedance in the device. Commercial semiconductor characterization systems with thecapability to characterize CNT materials and devices typically have input impedance values of 10’’ O to10’ 2 which is a recommended suitable range.
This test method requires that the instrumentation be calibrated against a known and appropriate set ofstandards (e.g.. National Institute of Standards and Technology (NIST)]. These calibrations may be performed by the equipment user provided the calibration is performed using the recommended calibrationprocedure called out by the equipment vendor or as a service by the equipment vendor. If calibration is notperformed against a known CNT reference or known device, then the basic instrument operations (e.g..yoltage, current, and resistance) shall be calibrated against some method traceable to a NIST (or similarinternationally recognized standards organization) physical standard. Recalibration is required according tothe instrument manufacturer’s recommendations, when the instrument is moved,or when the testingconditions change significantly (eg., temperature change greater than 10 °C, relative humidity (RH) changegreater than 30%,etc.).
1.3.2 Probing systems
Probing systems will be selected that have demonstrated the ability to provide data that is consistent innature and can be confirmed at various experimental labs. Probe tips will be chosen that were shown to beappropriate for the testing platform, In an effort to mitigate the potential for erroneous data, proceduresshould be followed to ensure that the probe tips are clean of contaminants. Therefore, probe tips must bestored in an environment that is devoid of contaminants and they must be handled following stringentprocedures during nanotube characterization to minimize contamination.
1.3.3 Measurement techniques
1.3.3.1 0hmic contact
Ohmic contact with a CNT is required in order to make the appropriate measurements.
Ohmic contact, as defined in the semiconductor industry, is a metallic-semiconductor contact with very lowresistance that is independent of applied voltage (may be represented by constant resistance). To form anohmic contact, the metal and the semiconductor materials must be selected such that there is no potentiabarrier formed at the interface (or the potential barrier is so thin that charge carriers can readily tunnelthrough it). Ohmic contacts show a linear correlation between current flowing through the contact and thevoltage drop across this interface
Non-ohmic contacts are evident when the potential difference across the contact is not linearly proportionalto the current flowing through it. This type of contact is often known as a rectifying or Schottky contactNon-ohmic contacts may occur in a low-voltage circuit as a result of non-linear connections
1.3.3.1.1 Suggested methods to check for ohmic contact
Several methods are suggested in 1.3.3.11.1 and 1.3.3.1.1.2 to check for ohmic contact and methods toachieve ohmic contact.
IEEE 1650-2005 pdf download
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