This incorporates a resistive thermal element at the end of the cantilever. The arms of the cantilever are made of silver wire. The advantage of this design is that it may be used in one of two modes allowing thermal imaging of sample temperature and thermal conductivity. The SThM can be used in two different operating modes, allowing thermal imaging of sample temperature and thermal conductivity. In the temperature contrast mode, the thermal probe is used as a resistance thermometer.
Temperature is monitored using a bridge circuit to measure the probe resistance.
The probe cur-rent is constant and the changes in the probe resistance during scanning reflect the surface temperature changes on the sample surface. In the conductivity contrast mode, the thermal probe is kept at a constant temperature. Changes in sample thermal conductivity affect the heat flow between the self-heating probe and the sample. This heat flow is monitored, as thermal conductivity, by measuring the voltage necessary to keep the probe at a constant temperature.