Anomalous Low Thermal Conductivity of Atomically Thin InSe Probed by Scanning Thermal Microscopy

Abstract

The ability of a material to conduct heat influences many physical phenomena, ranging from thermal management in nanoscale devices to thermoelectrics. Van der Waals 2D materials offer a versatile platform to tailor heat transfer due to their high surface‐to‐volume ratio and mechanical flexibility. Here, the nanoscale thermal properties of 2D indium selenide (InSe) are studied by scanning thermal microscopy. The high electrical conductivity, broad‐band optical absorption, and mechanical flexibility of 2D InSe are accompanied by an anomalous low thermal conductivity (κ). This can be smaller than that of low‐κ dielectrics, such as silicon oxide, and it decreases with reducing the lateral size and/or thickness of InSe. The thermal response is probed in free‐standing InSe layers as well as layers supported by a substrate, revealing the role of interfacial thermal resistance, phonon scattering, and strain. These thermal properties are critical for future emerging technologies, such as field‐effect transistors that require efficient heat dissipation or thermoelectric energy conversion with low‐κ, high electron mobility 2D materials, such as InSe.

Quantifying anisotropic thermal transport in two-dimensional perovskite (PEA2PbI4) through cross-sectional scanning thermal microscopy

“…The cross-sectioned 2D perovskite film was then transferred to the high vacuum chamber for SThM measurements that could image the thermal response with a high spatial resolution (~50 nm) in contrast to the far-field optical techniques [34,37]. It may be noted that a high vacuum is desirable to avoid additional heat transfer through air and the formation of water meniscuses at the tip apex [38][39][40].…”

“…When the probe is energized via DC and AC voltage and brought into close contact with the perovskite surface, a heat flow is generated from the tip to the sample due to a temperature gradient. This changes the temperature of the probe and hence the resistance of the probe which is monitored as the change of output voltage of the Wheatstone bridge [37]. The experimental data were fitted with an analytical model in MATLAB software.…”

Chloride-assisted synthesis of tellurene directly on SiO2/Si substrates: growth mechanism, thermal properties, and device applications

“…It is noted that the signal from the edge of flakes is variated probably due to the limited contact area and the unidirectional heat flow. 46,51 Please do not adjust margins Next, to explore the influence of thickness on the thermal property, tellurene flakes with different thickness, 11.2 nm, 18.6 nm and 26.7 nm were prepared for examination. The results are as shown in Figure 5(c).…”

Nanoscale Thermal Strain Engineering-Driven Ferroelastic Domain Evolution in CH3NH3PbI3 Perovskites

“…Atomic force microscopy (AFM)-based scanning thermal microscopy (SThM) has become a powerful tool to characterize local thermal physics. − In SThM, when an ac current is applied to a thermally resistant probe, it will be heated periodically and as the heated probe is in contact with the sample surface, a frequency-modulated local thermal stress will be generated in the sample. Here, such local thermal stress was incorporated into the MAPbI 3 crystal, resulting in alternative nanoscale dynamical thermal strains in crystals, which drive a very interesting ferroelastic domain evolution via ion migration.…”