Efficient waste heat dissipation has become increasingly challenging as transistor size has decreased to nanometers. As governed by universal Umklapp phonon scattering, the thermal conductivity of semiconductors decreases at higher temperatures and causes heat transfer deterioration under high-power conditions. In this study, we realized simultaneous electrical and thermal rectification (TR) in a monolayer MoSe
2
-WSe
2
lateral heterostructure. The atomically thin MoSe
2
-WSe
2
heterojunction forms an electrical diode with a high ON/OFF ratio up to 10
4
. Meanwhile, a preferred heat dissipation channel was formed from MoSe
2
to WSe
2
in the ON state of the heterojunction diode at high bias voltage with a TR factor as high as 96%. Higher thermal conductivity was achieved at higher temperatures owing to the TR effect caused by the local temperature gradient. Furthermore, the TR factor could be regulated from maximum to zero by rotating the angle of the monolayer heterojunction interface. This result opens a path for designing novel nanoelectronic devices with enhanced thermal dissipation.
This paper presents a new integrated H-type method for precisely characterizing the thermoelectric properties of suspended two-dimensional (2D) materials. The current method combines the micro-device electrical measurement and laser heating together. The electrical measurement offers high accuracy, while the measurement principle and operation can be much simplified by using the noncontact laser heat source. The 2D material is suspended between two metallic nanofilms to form a H-type structure, i.e. named as H-type method. The metallic nanofilms can be used as an electrical Joule heater and a temperature sensor. By simply changing the external circuit, the electrical conductivity, thermal conductivity and Seebeck coefficient can be measured on the same nanomaterial sample, simultaneously. Thus, the main origin of measurement uncertainty caused by the sample discrepancy can be avoided. In the measurement, the laser absorption rate of the 2D material can be obtained as well. Taking monolayer graphene as an example, a detailed uncertainty analysis was carried out. This work provides a reliable and accurate measurement method to achieve full thermoelectric properties of 2D materials, setting a foundation for practical design of efficient 2D thermoelectric devices.
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