Optical Phonon Scattering Dominated Transport in Individual Suspended Carbon Nanotubes

The transport property of six types of individual carbon nanotubes (CNT) with specified chiral indices at high temperature is investigated on a home-made apparatus. It is found that the resistivity of all individual CNTs increases with temperature monotonically, whereas the mobility decreases with temperature and follows different laws in different temperature ranges. The carrier concentration increases exponentially with -1/T. The mobility of CNT deviates from traditional trends with temperature,T-beta, at high temperature (1070-1728 K). This deviation is attributed to scattering with optical phonons at high temperature. The data show that the electron-optical phonon interaction becomes dominant in the temperature range of 1070-1362 K for all measured CNTs. Finally, result within a polaron model is discussed.