Wednesday, 17 July 2024

Intrinsic Nature of Graphene Revealed in Temperature-Dependent Transport of Twisted Multilayer Graphene

U. Mogera, S. Walia, B. Bannur, M. Gedda and G. U. Kulkarni
J. Phys. Chem. C, 121 (25), 13938–13943 (2017)


Graphene in its purest form is expected to exhibit a semiconducting to metallic transition in its temperature dependent conductivity with a transition temperature, Tc, depending sensitively on the disorder or defects present in it. Even for good quality graphene, these disorder are non-negligible and the transition temperature appears above the ambient, practically rendering it to be only semiconducting over a wide range of temperature. Here we show, an experimental study on the transport behaviour of decoupled twisted multilayer graphene (tMLG) exhibiting Tc well below the ambient temperature. The graphene layers in these tMLG are highly decoupled with one another due to the angular rotation among them, as a result, they exhibit very high Raman I2D/IG values (up to 12) with narrow 2D width (16 – 24 cm-1). The photoresponse behaviour also corroborates well with the transition in transport behaviour.

Posted by Dr. U. Mogera