Department of Chemical Engineering, University of Illinois at Chicago , 810 S. Clinton Street, Chicago, Illinois 60607, United States.
SunEdison Semiconductor , 501 Pearl Drive, Saint Peters, Missouri 63376, United States.
ACS Nano. 2017 May 23;11(5):4985-4994. doi: 10.1021/acsnano.7b01666. Epub 2017 May 1.
Hexagonal boron nitride (h-BN) is an ideal platform for interfacing with two-dimensional (2D) nanomaterials to reduce carrier scattering for high-quality 2D electronics. However, scalable, transfer-free growth of hexagonal boron nitride (h-BN) remains a challenge. Currently, h-BN-based 2D heterostructures require exfoliation or chemical transfer of h-BN grown on metals resulting in small areas or significant interfacial impurities. Here, we demonstrate a surface-chemistry-influenced transfer-free growth of large-area, uniform, and smooth h-BN directly on silicon (Si)-based substrates, including Si, silicon nitride (SiN), and silicon dioxide (SiO), via low-pressure chemical vapor deposition. The growth rates increase with substrate electronegativity, Si < SiN < SiO, consistent with the adsorption rates calculated for the precursor molecules via atomistic molecular dynamics simulations. Under graphene with high grain density, this h-BN film acts as a polymer-free, planar-dielectric interface increasing carrier mobility by 3.5-fold attributed to reduced surface roughness and charged impurities. This single-step, chemical interaction guided, metal-free growth mechanism of h-BN for graphene heterostructures establishes a potential pathway for the design of complex and integrated 2D-heterostructured circuitry.
六方氮化硼（h-BN）是与二维（2D）纳米材料接口的理想平台，可减少载流子散射，从而获得高质量的 2D 电子器件。然而，可扩展、无转移的六方氮化硼（h-BN）的生长仍然是一个挑战。目前，基于 h-BN 的 2D 异质结构需要剥离或化学转移在金属上生长的 h-BN，这导致了较小的面积或显著的界面杂质。在这里，我们通过低压化学气相沉积，在包括硅（Si）、氮化硅（SiN）和二氧化硅（SiO）在内的基于 Si 的衬底上，展示了一种受表面化学影响的无转移、大面积、均匀和光滑 h-BN 的直接生长。在具有高密度晶粒的石墨烯上，这种 h-BN 薄膜作为无聚合物的平面介电界面，将载流子迁移率提高了 3.5 倍，这归因于表面粗糙度和带电杂质的减少。这种用于石墨烯异质结构的 h-BN 的单步、化学相互作用引导、无金属生长机制为设计复杂和集成的 2D 异质结构电路建立了一个潜在途径。
