Synthesis and Characterization of Hexagonal Boron Nitride Film as a Dielectric Layer for Graphene Devices
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- 作者：Ki Kang Kim ; Allen Hsu ; Xiaoting Jia ; Soo Min Kim ; Yumeng Shi ; Mildred Dresselhaus ; Tomas Palacios ; Jing Kong
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：October 23, 2012
- 年：2012
- 卷：6
- 期：10
- 页码：8583-8590
- 全文大小：466K
- 年卷期：v.6,no.10(October 23, 2012)
- ISSN：1936-086X
文摘
Hexagonal boron nitride (h-BN) is a promising material as a dielectric layer or substrate for two-dimensional electronic devices. In this work, we report the synthesis of large-area h-BN film using atmospheric pressure chemical vapor deposition on a copper foil, followed by Cu etching and transfer to a target substrate. The growth rate of h-BN film at a constant temperature is strongly affected by the concentration of borazine as a precursor and the ambient gas condition such as the ratio of hydrogen and nitrogen. h-BN films with different thicknesses can be achieved by controlling the growth time or tuning the growth conditions. Transmission electron microscope characterization reveals that these h-BN films are polycrystalline, and the c-axis of the crystallites points to different directions. The stoichiometry ratio of boron and nitrogen is close to 1:1, obtained by electron energy loss spectroscopy. The dielectric constant of h-BN film obtained by parallel capacitance measurements (25 渭m2 large areas) is 2鈥?. These CVD-grown h-BN films were integrated as a dielectric layer in top-gated CVD graphene devices, and the mobility of the CVD graphene device (in the few thousands cm2/(V路s) range) remains the same before and after device integration.