Solution-Processed Dielectrics Based on Thickness-Sorted Two-Dimensional Hexagonal Boron Nitride Nanosheets.
Gate dielectrics directly affect the mobility, hysteresis, power consumption, and other critical device metrics in high-performance nanoelectronics. With atomically flat and dangling bond-free surfaces, hexagonal boron nitride (h-BN) has emerged as an ideal dielectric for graphene and related two-dimensional semiconductors. While high-quality, atomically thin h-BN has been realized via micromechanical cleavage and chemical vapor deposition, existing liquid exfoliation methods lack sufficient control over h-BN thickness and large-area film quality, thus limiting its use in solution-processed electronics. Here, we employ isopycnic density gradient ultracentrifugation for the preparation of monodisperse, thickness-sorted h-BN inks, which are subsequently layer-by-layer assembled into ultrathin dielectrics with low leakage currents of 3 × 10(-9) A/cm(2) at 2 MV/cm and high capacitances of 245 nF/cm(2). The resulting solution-processed h-BN dielectric films enable the fabrication of graphene field-effect transistors with negligible hysteresis and high mobilities up to 7100 cm(2) V(-1) s(-1) at room temperature. These h-BN inks can also be used as coatings on conventional dielectrics to minimize the effects of underlying traps, resulting in improvements in overall device performance. Overall, this approach for producing and assembling h-BN dielectric inks holds significant promise for translating the superlative performance of two-dimensional heterostructure devices to large-area, solution-processed nanoelectronics.
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Jian
J
Zhu
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Joohoon
J
Kang
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Junmo
J
Kang
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Deep
D
Jariwala
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Joshua D
JD
Wood
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Jung-Woo T
JW
Seo
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Kan-Sheng
KS
Chen
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Tobin J
TJ
Marks
Department of Materials Science and Engineering, ‡Graduate Program in Applied Physics, §Department of Chemistry, and ∥Department of Medicine, Northwestern University , Evanston, Illinois 60208, United States.
Mark C
MC
Hersam
D001896:Boron Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures; D012996:Solutions
D001896:Boron Compounds; D012996:Solutions; C017282:boron nitride
Density gradient ultracentrifugation; density differentiation; graphene; h-BN; heterostructure; isopycnic sorting