University of Oxford,
Keywords: olihomeric aminoborane, chemical vapour deposition CVD, hexagonal born nitride h-BN
Summary:In summary, we have synthesized few-layered h-BN films on Cu substrates by the APCVD method using three different precursors. Two precursors, diborazane, H3B·NH2BH2·NH3(DAB), and trimeric triborazane, H3B·(NH2BH2)2·NH3(TAB), both derivatives of ammonia borane, H3B·NH3(AB), show success in growing h-BN. When comparing the resulting h-BN film growth morphology with the AB precursor, 30 minutes growth duration results in continuous h-BN film formation on Cu substrates for all the precursors. The overall surface nanoparticle coverage shows dependence of the precursor molecular weight. The grown h-BN films are characterized via Raman microscopy, AFM, and TEM, indicating that the grown h-BN films are 2–5 nm thick and crystalline. Because the surface of Cu is the same for all three precursors, we can link the difference in growth rates to different precursor decomposition processes. The main driving factor controlling the variable growth will be the molecular gaseous species emitted from the heated precursors, in terms of its chemical structure and rate of emission. Future work incorporating mass spectroscopy to measure the chemical species emitted from each solid state precursor upon heating may help shed more light on this topic. This work offers an insight into the variety of precursors that can be used for the CVD growth of h-BN.