Thermodynamics of carbon point defects in hexagonal boron nitride

Abstract

We present a first-principles computational study of the thermodynamics of carbon defects in hexagonal boron nitride (hBN). The defects considered are carbon monomers, dimers, trimers, and larger carbon clusters, as well as complexes of carbon with vacancies, antisites, and substitutional oxygen. Our calculations show that monomers (C B , C N ), dimers, trimers, and C N O N pairs are the most prevalent species under most growth conditions. Compared to these defects, complexes of carbon with vacancies and antisites occur at much smaller concentrations (<10 14 cm −3 ). Our results are discussed in view of the relevance of carbon defects in singlephoton emission in hBN.

Ultraviolet quantum emitters in $h$-BN from carbon clusters

“…By contrast, the defects with an odd number of carbons rapidly change their charge states across the formation energy diagrams owing to their radical nature. Our calculations provide a low formation energy of 2.17 eV the carbon dimer C N C B which agrees well with the previous reports [26,32]. In addition, the formation energy of 6C ring is found 1.2 eV larger than that for the dimer (0.5 eV with PBE [33] functionals) and this is the second lowest formation energy.…”

“…We acknowledge that the results of this research have been achieved using the DECI resource Eagle based in Poland at Poznan with support from the PRACE aisbl. During the paper submission, a paper about thermodynamics of carbon point defects in hBN by Maciaszek et al has appeared on arXiv [32].…”