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Multiwalled carbon nanotube field effect transistors (MWCNT-FETs) are often built on Si wafers covered with a dielectric layer of SiO2 . The Si wafer acts as a back-gate with which the conductance of a semiconducting nanotube can be controlled. We have studied the performance of MWCNT-FETs both at room temperature as well as at cryogenic temperatures. It is shown here that the transistors may exhibit hysteresis in their transfer characteristics at room temperature which may be due to mobile charge carriers in the dielectric. Lowering the temperature reduces significantly the hysteresis in the MWCNT-FETs. While hysteresis is unwanted for a FET, it may be useful for memory applications. |