Transport properties of HfO$_{2}$ top-gated bilayer graphene field effect transistors
ORAL
Abstract
We present the fabrication and electrical transport studies of SiO$_{2}$/HfO$_{2}$ double-gated bilayer graphene field effect transistors (FETs). The top gate dielectric layer is formed by depositing 30nm HfO$_{2}$ onto graphene FETs fabricated on conventional SiO$_{2}$/doped Si substrates, using low temperature atomic layer deposition without the use of an adhesion layer. The top gate has an excellent gating efficiency of $\sim$2.8x10$^{12}$/cm$^{2}$V, which is 40 times larger than that of the Si backgate and can reach carrier density 1.4x10$^ {13}$/cm$^{2}$. We observe electron mobility up to 6,000 cm$^{2} $/Vs in double-gated bilayers. Pristine bilayer graphene on SiO$_{2}$, on the other hand, exhibits $\mu$ = 12,000 cm$^{2} $/Vs. We report and discuss the temperature-dependent conductivity in double and single-gated bilayer graphene at different densities and bias electric fields.
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Authors
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K. Zou
The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Penn State University, Physics Department, Penn State University
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J. Zhu
Physics Department, Penn State University, Pennsylvania State University, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Penn State University, Department of Physics, Penn State University