Scanning Thermal Microscope Based on AFM

Various types of heat probe are used in the AFM-based thermal microscope (a) thermocouple tip and (b) thermoresistive tip. The thermoelectric voltage is directly proportional to the temperature when using a thermocouple tip. A sample thermocouple tip is shown in [Pg.442]

Rp is the electrical resistance of the tip at reference temperature TpQ and Up is the temperature coefficient of electrical resistivity. [Pg.444]

The thermal probe can be used in either passive mode or active mode as described later. [Pg.444]

The thermal probe is used as a resistive thermometer in passive mode. A small constant current (1-2 mA) is applied such that Joule heating of the tip can be assumed negligible. The temperature change at the sample surface can cause a temperature variation (ATp) in the tip during scan. This temperature variation can cause a change in electrical resistance of the probe [Pg.444]

The change in electrical resistance leads to change in the voltage output from the circuit. The variation of this voltage is an indication of local heating at the sample surface. [Pg.444]

Big Chemical Encyclopedia