Amorphous silicon-boron-nitride networks

In recent years, atomistic simulations are assuming a guiding role in the effort of optimizing the properties of advanced coating materials (Lawson et al., J Appl Phys 110:083507, 2011; Kindlund et al., APL Mater 1:042104, 2013; Tang et al., J Phys Chem C 119:24649–24656, 2015; Zhang et al., Surf Coat Technol 277:136–143, 2015; Ni et al., Appl Phys Lett 107:031603, 2015). In amorphous Silicon-Boron-Nitride networks (a-Si-B-N), understanding the role played by composition is of great importance for the future design of this new material. So far, a-Si-B-N structures have been explored to understand the impact of the BN:Si₃N₄ ratio onto mechanical properties (Tang et al., Chem Eur J 16:6458–6462, 2010; Schön et al., Process Appl Ceram 5:49–61, 2011; Griebel and Hamaekers, Comput Mater Sci 39:502–517, 2007; Ge et al., Adv Appl Ceram 113:367–371, 2014). Using classical molecular dynamics (MD) simulations, Griebel and Hamaekers (Comput Mater Sci 39:502–517, 2007) derived strain-stress curves of selected a-Si₃BN₅, a-Si₃B₂N₆, and a-Si₃B₃N₇ models and found that increasing the B content increases Young’s modulus. In this chapter, we extend the scope of the previous studies by revealing how composition and structure might influence a combination of properties desirable for coating applications. Using a combination of atomistic numerical methods, we screen a library of low enthalpy a-Si-B-N networks (a-Si₃BN₅, a-Si₃B₃N₇, and a-Si₃B₉N₁₃) to predict from extensive atomistic simulations the thermal conductivity (κ) and mechanical stiffness with different BN contents.