Large-area synthesis of hexagonal boron nitride (hBN) with monocrystallinity and tunable thickness using chemical vapor deposition (CVD)

Hexagonal boron nitride (hBN) is the preeminent 2D insulator because of its exceptional properties, including high thermal/chemical stability, high thermal conductivity, and room-temperature single-photon emission. Additionally, its atomically smooth, dangling-bond-free surface with minimal charge puddles makes hBN a remarkable dielectric passivation layer in ultra-high mobility transistors and devices exhibiting novel condensed matter physics. However, the development of hBN technologies has been severely limited because the materials quality of hBN produced using chemical vapor deposition (CVD), a scalable technique compatible with semiconductor processing, is currently inferior to that of hBN produced using mechanical exfoliation, an inherently small-area, low-throughput process. In this talk, we will demonstrate that by tailoring the catalyst substrate and CVD growth conditions, large-area films of single-crystal hBN and hBN with tunable thickness from <1 to 30 nm can be synthesized. Extensive synthesis studies elucidate the growth dynamics and mechanisms on Ge, Cu, and Ni substrates using borazine as the precursor. The properties of our large-area CVD hBN films will be compared to those of micron-scale exfoliated hBN flakes, and single-photon emission measurements will be presented. These results provide a path toward the wafer-scale production of device-quality hBN films with precisely controlled thickness.