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Transient Response of h-BN-Encapsulated Graphene Transistors: Signatures of Self-Heating and Hot-Carrier Trapping
Author(s)
Nathawat, Jubin
Zhao, Miao
Kwan, Chun Pui
Yin, Shenchu
Arabchigavkani, Nargess
Randle, Michael
He, Guanchen
Matsumoto, Naoki
Sakanashi, Kohei
Kida, Michio
Aoki, Nobuyuki
Jin, Zhi
Kim, Yunseob
Kim, Gil Ho
Watanabe, Kenji
Taniguchi, Takashi
Bird, Jonathan P.
Date Issued
February 22, 2019
Type
Article
Abstract
We use transient electrical measurements to investigate the details of self-heating and charge trapping in graphene transistors encapsulated in hexagonal boron nitride (h-BN) and operated under strongly nonequilibrium conditions. Relative to more standard devices fabricated on SiO 2 substrates, encapsulation is shown to lead to an enhanced immunity to charge trapping, the influence of which is only apparent under the combined influence of strong gate and drain electric fields. Although the precise source of the trapping remains to be determined, one possibility is that the strong gate field may lower the barriers associated with native defects in the h-BN, allowing them to mediate the capture of energetic carriers from the graphene channel. Self-heating in these devices is identified through the observation of time-dependent variations of the current in graphene and is found to be described by a time constant consistent with expectations for nonequilibrium phonon conduction into the dielectric layers of the device. Overall, our results suggest that h-BN-encapsulated graphene devices provide an excellent system for implementations in which operation under strongly nonequilibrium conditions is desired.
Citation
ACS Omega, 4(2), 4082-4090, 2019