Role of hydrogen in the growth of boron nitride: Cubic phase versus hexagonal phase

Hydrogen (H) behavior in crystal boron nitride (BN) has been systematically investigated by first-principles calculation. We find that H prefers to reside in the hexagonal phase (hBN) rather than the cubic phase (cBN). These kinds of H tend to gather to form clusters. In hBN, H can terminate a framework around an impurity-induced sp3 nucleus, thereby suppressing the cBN growth. This explains why there is no significant improvement in the hBN-to-cBN transition after aluminium (Al) doping.