Trimethylamine Borane: A New Single-Source Precursor for Monolayer h-BN Single Crystals and h-BCN Thin Films

Abstract

Due to their exceptional chemical and thermal stabilities as well as electrically insulating property, atomically thin hexagonal boron nitride (h-BN) films have been identified as a promising class of dielectric substrate and encapsulation material for high-performance two-dimensional (2D) heterostructure devices. Herein, we report a facile chemical vapor deposition synthesis of large-area atomically thin h-BN including monolayer single crystals and C-doped h-BN (h-BCN) films utilizing a relatively low-cost, commercially available trimethylamine borane (TMAB) as a single-source precursor. Importantly, pristine 2D h-BN films with a wide band gap of ∼6.1 eV can be achieved by limiting the sublimation temperature of TMAB at 40 °C, while C dopants are introduced to the h-BN films when the sublimation temperature is further increased. The h-BCN thin films displayed band gap narrowing effects as identified by an additional shoulder at 205 nm observed in their absorbance spectra. Presence of N−C bonds in the h-BCN structures with a doping concentration of ∼2 to 5% is confirmed by X-ray photoelectron spectroscopy. The inclusion of low C doping in the h-BN films is expected to result in constructive enhancement to its mechanical properties without significant alteration to its electrically insulating nature. This study provides new insights into the design and fabrication of large-area atomically thin h-BN/h-BCN films toward practical applications and suggests that the range of precursors can be potentially extended to other anime borane complexes as well.

Chemical vapor deposition growth of boron–carbon–nitrogen layers from methylamine borane thermolysis products

“…Therefore, the composition of the obtained B-C-N layers can be expressed as (BN)0.25-(C0.9N0.1)0.75. Our results essentially agree with previous ones in the fact that segregation of C-rich (Gr-like) and h-BN domains takes place in the obtained layers [7,8,10,11]. However, our results show a significant C-N bonding coming from C-N interactions at the Gr/h-BN interfaces and to N doping in Gr domains.…”

Metallfreie Bor‐haltige Heterogenkatalysatoren

“…Eine weitere Optimierung von Borcarbid könnte aber schwierig werden, hauptsächlich wegen der extremen Bedingungen, die für die Synthese dieses Materials erforderlich sind. Ein rationales Vorstufen‐Design kann eine effektive Strategie hin zu günstigeren Synthesebedingungen sowie zur Steuerung der chemischen und physikalischen Konfigurationen der Produkte sein . Eine solche Vorstufe kann als Dotierungsmittel funktionieren oder als dominierendes Startmaterial für die Synthese anderer Katalysatoren in dieser Gruppe dienen.…”

“…4000 °C. Daher gab es nur wenige signifikante Fortschritte ausgehend von Bor‐verknüpften Verbindungen durch rationales Design, man glaubt aber, dass diese Entwicklungen zu einem erneuerten Interesse an Bor‐haltigen Katalysatormaterialien führen könnten.…”

Probing the Atomic Structures of Synthetic Monolayer and Bilayer Hexagonal Boron Nitride Using Electron Microscopy

“…Fig. 1A-H shows the SEM images of h-BN grown on various Cu substrates under different growth conditions (Tay et al, 2014a(Tay et al, , 2014b(Tay et al, , 2016a(Tay et al, , 2016b. From these images, we can accurately account for the different shapes and sizes of the single-crystal domains.…”