Incorporating 2D materials like graphene - which is composed of a single-atom-thick layer of carbon atoms - into these components allows them to be several orders of magnitude smaller than if they were made with conventional, 3D materials. In addition, 2D materials also enable other unique functionalities. But, nanoelectronic components with 2D materials are prone to overheating due to poor heat conductance from 2D materials to the silicon base.
"In the field of nanoelectronics, the poor heat dissipation of 2D materials has been a bottleneck to fully realising their potential in enabling the manufacture of ever-smaller electronics while maintaining functionality," said Associate Professor Amin Salehi-Khojin of UIC.
"Bonds between the 2D materials and the silicon substrate are not very strong, so when heat builds up in the 2D material, it creates hot spots causing overheat and device failure," added Zahra Hemmat, co-first author of the research paper.
In order to enhance the connection between the 2D material and the silicon base to improve heat conductance away from the 2D material into the silicon, engineers have experimented with adding an additional ultra-thin layer of material on top of the 2D layer - in effect creating a ‘nano-sandwich’ with the silicon base and ultrathin material as the ‘bread.’
"By adding another 'encapsulating' layer on top of the 2D material, we have been able to double the energy transfer between the 2D material and the silicon base," Assoc Prof. Salehi-Khojin said.
The UIC team created an experimental transistor using silicon oxide for the base, carbide for the 2D material and aluminium oxide for the encapsulating material. At room temperature, the researchers saw that the conductance of heat from the carbide to the silicon base was twice as high with the addition of the aluminium oxide layer versus without it.
"While our transistor is an experimental model, it proves that by adding an additional, encapsulating layer to these 2D nanoelectronics, we can significantly increase heat transfer to the silicon base, which will go a long way towards preserving functionality of these components by reducing the likelihood that they burn out," said Assoc Prof. Salehi-Khojin. "Our next steps will include testing out different encapsulating layers to see if we can further improve heat transfer."
