First-Principles Studies of Photoluminescence of Defects in Semiconductors

Optically active points defects in semiconductors offer unique opportunities for quantum technology applications, and accurate predictions of their opto-electronic properties may help design efficient systems for, e.g. quantum emitters. Here we present a general strategy to compute photoluminescence (PL) spectra of point defects from first principles, as well as results for several systems, including the negatively charged nitrogen-vacancy center in diamond, the neutral divacancy in silicon carbide and the carbon-dimer substituent in hexagonal boron nitride. Using the Franck-Condon principle, we computed zero-phonon lines, phonon sidebands and Huang-Rhys factors and we performed a detailed analysis of the electron-phonon coupling of optical transitions. We discuss the results obtained using different methods to compute excited state properties, including constrained density functional theory (CDFT) and time-dependent density functional theory (TDDFT).