Role of Pressure in the Growth of Hexagonal Boron Nitride Thin Films from Ammonia-Borane

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• 作者：Justin C. Koepke ; Joshua D. Wood ; Yaofeng Chen ; Scott W. Schmucker ; Ximeng Liu ; Noel N. Chang ; Lea Nienhaus ; Jae Won Do ; Enrique A. Carrion ; Jayan Hewaparakrama ; Aniruddh Rangarajan ; Isha Datye ; Rushabh Mehta ; Richard T. Haasch ; Martin Gruebele ; Gregory S. Girolami ; Eric Pop ; Joseph W. Lyding
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：June 28, 2016
• 年：2016
• 卷：28
• 期：12
• 页码：4169-4179
• 全文大小：727K
• 年卷期：0
• ISSN：1520-5002

文摘

We analyze the optical, chemical, and electrical properties of chemical vapor deposition (CVD) grown hexagonal boron nitride (h-BN) using the precursor ammonia-borane (H₃N–BH₃) as a function of Ar/H₂ background pressure (P_TOT). Films grown at P_TOT ≤ 2.0 Torr are uniform in thickness, highly crystalline, and consist solely of h-BN. At larger P_TOT, with constant precursor flow, the growth rate increases, but the resulting h-BN is more amorphous, disordered, and sp³-bonded. We attribute these changes in h-BN grown at high pressure to incomplete thermolysis of the H₃N–BH₃ precursor from a passivated Cu catalyst. A similar increase in h-BN growth rate and amorphization is observed even at low P_TOT if the H₃N–BH₃ partial pressure is initially greater than the background pressure P_TOT at the beginning of growth. h-BN growth using the H₃N–BH₃ precursor reproducibly can give large-area, crystalline h-BN thin films, provided that the total pressure is under 2.0 Torr and the precursor flux is well-controlled.