Nanoscale thermal probing

Abstract

Nanoscale novel devices have raised the demand for nanoscale thermal characterization that is critical for evaluating the device performance and durability. Achieving nanoscale spatial resolution and high accuracy in temperature measurement is very challenging due to the limitation of measurement pathways. In this review, we discuss four methodologies currently developed in nanoscale surface imaging and temperature measurement. To overcome the restriction of the conventional methods, the scanning thermal microscopy technique is widely used. From the perspective of measuring target, the optical feature size method can be applied by using either Raman or fluorescence thermometry. The near-field optical method that measures nanoscale temperature by focusing the optical field to a nano-sized region provides a non-contact and non-destructive way for nanoscale thermal probing. Although the resistance thermometry based on nano-sized thermal sensors is possible for nanoscale thermal probing, significant effort is still needed to reduce the size of the current sensors by using advanced fabrication techniques. At the same time, the development of nanoscale imaging techniques, such as fluorescence imaging, provides a great potential solution to resolve the nanoscale thermal probing problem.

Keywords: Raman spectroscopy resistance thermometry; feature size; nanoscale; near-field; scanning thermal microscopy.

Fig. 1

Schematic of the scanning thermal microscope (SThM) based on AFM, the temperature sensor is attached at the apex of the tip. Reproduced with permission from Reference (1). American Institute of Physics, Copyright (2003).

Fig. 2

(a) Spectrum of a single CdSe quantum dots at different temperatures, a slope of 0.105 nm/K is obtained for the relationship between wavelength and temperature; (b) Temperature dependence of fluorescence intensity; (c) Temperature dependence of fluorescence peak width. Reproduced with permission from Reference (36). American Chemical Society, Copyright (2007).

Fig. 3

The linear relationship between temperature and Raman shift of various peaks of SWCNT ring. Reproduced with permission from Reference (49). American Institute of Physics, Copyright (2008).

Fig. 4

(a) Schematic of micro/nanoscale spatial resolution temperature probing for interfacial thermal characterization between epitaxial graphene and 4H-SiC; (b) Calibration result of temperature dependence of Raman shift. Reproduced with permission from Reference (52). John Wiley and Sons, Copyright (2011).

Fig. 5

Schematic of nanoscale temperature measurement under tip-induced near-field heating effect, sub-10 nm spatial resolution was obtained in this experiment. Reproduced with permission from Reference (9). American Chemical Society, Copyright (2011).

Fig. 6

(a) The diagram of single Ag nanoparticle attached to the tip for the near-field effect; (b) Enhanced Raman spectrum of the sample (3-hydroxykynurenine). Reproduced with permission from Reference (57). American Chemical Society, Copyright (1997).

Fig. 7

(a) The conductance of silicon nanowires is in linear relationship with temperature; (b) Temperature dependence of resistance of CNT film, the temperature coefficient of resistance changes with temperature. Reproduced with permission from Reference (70) and (69). Elsevier, Copyright (2008) and American Institute of Physics, Copyright (2009).