Scanning Thermal Microscopy

Abstract

This chapter presents a review of the technology of scanning thermal microscopy (SThM) and its applications in thermally probing micro-and nanostructured materials and devices. We begin by identifying the parameters that control the temporal and temperature resolution in thermometry. The discussion of SThM research is divided into three main categories: those that use (a) thermovoltage-based measurements, (b) electrical resistance techniques, and (c) thermal expansion measurements. Within each category we describe numerous techniques developed for (a) the method of probe fabrication, (b) the experimental setup used for SThM, (c) the applications of that technique, and (d) the measurement characteristics such as tip-sample heat transfer mechanism, spatiotemporal resolution, and interpretation of data for property measurements. Because most of the SThM techniques require fundamental knowledge of tip-sample heat transfer, all possible heat transfer mechanisms are discussed in depth, and relations for estimating the tip-sample conductance for each mechanism are provided. This is critical because tip-sample heat transfer controls spatial resolution, temperature accuracy and resolution, and imaging artifacts. Based on this discussion, a simple model is given for future design of SThM probes. The review concludes by describing some new developments on the applications of near-field optical microscopy for temperature measurements.

Nanoscale thermal imaging of dissipation in quantum systems

“…Consequently, in the case of suspended nanowires the ( , ) reflects the temperature of the nanowires as well as the background temperature of the substrate in-between the wires. In contrast, contact-based vacuum SThM [11][12][13][14][15] would detect only the temperature of the suspended nanowires if scanning at a height corresponding to the top surface plane of the nanowires.…”

“…Despite its vital importance the microscopic behavior of a system is usually not formulated in terms of dissipation because the latter is not a readily measureable quantity on the microscale. Although nanoscale thermometry is gaining much recent interest [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] , the existing thermal imaging methods lack the necessary sensitivity and are unsuitable for low temperature operation required for study of quantum systems. Here we report a superconducting quantum interference nano-thermometer device with sub 50 nm diameter that resides at the apex of a sharp pipette and provides scanning cryogenic thermal sensing with four orders of magnitude improved thermal sensitivity of below 1 µK/Hz 1/2 .…”

“…Such signals are several orders of magnitude below the best sensitivity of several mK Hz 1 2 ⁄ ⁄ of any of the existing imaging techniques [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] (Fig. 1a) including radiation-based thermometry utilizing infra-red 6 , fluorescence in nanodiamonds 4,7,8 , Raman 9 , or transmission electron beam 5 , and atomic force microscopy (AFM) outfitted with thermocouple or resistive thermometers [10][11][12][13][14][15] . Moreover, none of the existing imaging techniques was demonstrated to operate at sufficiently low temperatures that are essential for study of quantum systems.…”

Quantification of probe–sample interactions of a scanning thermal microscope using a nanofabricated calibration sample having programmable size

“…This is compounded by the fact that, in passive mode, the probe temperature is always lower than that of the sample as a result of the thermal resistance of the tip-sample contact [1][11] [12].…”

Nanoscale resolution scanning thermal microscopy using carbon nanotube tipped thermal probes

“…11,12 Scanning thermal microscopy (SThM) [11][12][13][14][15][16][17][18][19] has come a long way since its invention 11 in 1986 and currently plays a leading role in the investigation of thermal properties on the nanoscale. SThM use a self-heating thermal sensors incorporated within a sharp tip that is thermally contacted with a sample surface and is widely used in studies of polymeric and organic materials 15 .…”