Reported by Associate Prof. Chunrui MA
Graphene, a monolayered carbon material with a hexagonal structure, has been considered as a promising material for high-performance nanoelectronics due to its superior chemical stability, high electron mobility, mechanical flexibility and high transmittance. Especially, the ambipolar characteristics of graphene based on field effect transistors (GFETs) make them highly competitive with the present electronic devices, since the graphene can behave as n-type or p-type by doping. Until now, great efforts have been performed to modulate the doping in graphene, such as UV radiation in different gas environments, absorption of ionic liquid/ionic gel or gas molecules. However, these doping methods will introduce the second phase and it is irrecoverable.
Recently, the functional materials center of our department has designed a new all-inorganic flexible graphene field effect transistor (GFET). A designable doping effect is achieved by utilizing the flexoelectric effect of ferroelectric Pb0.92La0.08Zr0.52Ti0.48O3 thin film. By gradually increasing the bending strain (the decrease of upward/downward bending radius), the Dirac point (VDirac) linearly shifts to left/right. Compared to other methods, the mechanical stress/strain tunable has three advantages: (i) it does not involve the absorption from secondary substances like gas molecules or ionic liquids; (ii) it is recoverable without any change on graphene; (iii) the doping operation is simple and reliable. Based on these merits, our designed GFET not only offers an easy, controllable and nonintrusive method to obtain a specific doping graphene for flexible electric device, but also can be used as a sensor to detect the bending state according to the change of VDirac.
This research was recently published in an international top journal, Materials Horizons（IF=13.183）, with the title of " Controlling the Dirac point voltage of graphene by mechanically bending the ferroelectric gate of graphene field effect transistor " and it is selected as the inside back cover. Xi'an Jiaotong University is the affiliation of first author and the first corresponding author in this paper. Associated Prof. Chunrui Ma is the corresponding author and the first author, Guangliang Hu, is a co-supervised Ph.D candidate by Associated Prof. Chunrui Ma and Prof. Chunlin Jia.
This work is supported by national science foundation, national “973” projects of China, NSF and so on.
Paper Link：https://pubs.rsc.org/en/content/articlelanding/2019/mh/c8mh01499j#!divAbstract
