Scanning thermal microscopy
Scanning thermal microscopy (SThM) is a type of scanning probe microscopy that maps the local temperature and thermal conductivity of an interface.
The probe in a scanning thermal microscope is sensitive to local temperatures – providing a nano-scale thermometer.
Thermal measurements at the nanometer scale are of both scientific and industrial interest.
These measurements can include: temperature, thermal properties of materials, thermal conductivity, heat capacity, glass transition temperature, latent heat, enthalpy, etc.
Through a calibration process, the SThM can reveal the quantitative values of thermal conductivity.
(a) Schematics of experimental setup. An electric current is applied to the arms of an AFM cantilever ( phosphorus -doped Si, P:Si) and heats up the end section above the tip ( intrinsic Si, i -Si). The bottom lens excites a diamond nanocrystal with a green laser light and collects photoluminescence (PL). The crystal hosts an N-V center and is attached to the AFM tip. A wire on the sample surface serves as the microwave source (mw). The temperature of the cantilever T h is determined from the applied current and voltage.
(b) Optically detected magnetic resonance spectra of the N-V center at three temperatures.
(c) Thermal conductivity image of a gold letter E on sapphire . White circles indicate features that do not correlate with the AFM topography. (d) PL image of the AFM cantilever end and tip where the diamond nanocrystal appears as the bright spot. (e) Zoomed PL image of the N-V center in d. [ 2 ]
