Quantitative temperature mapping of carbon nanotube using null point method

Despite the high spatial resolution of scanning thermal microscope, its usefulness has been limited because of its lack of quantitative measurement. In this study, utilizing the principle of double scan technique, we developed the null-point method by which one can measure the temperature of a nanoscale sample quantitatively without the disturbances due to the heat transfer through the air and the variation of tip-sample conductance caused by the change of tip-sample contact area. We first checked the effectiveness and accuracy of null point method using 5 μm and 400 nm wide aluminium line whose temperature can be easily controlled and measured. Then, we measured the temperature of electrically heated multi-walled carbon nanotube (MWCNT) via null point method and the temperature profile around it using double scan technique.