First-Principles High-Throughput Analysis of Wide Band Gap Semiconductors for Optical Applications

Relying on first-principles calculations, a database with the static refractive index and the bandgap of more than 4000 inorganic semiconductors is created. The inverse relationship between these two quantities is confirmed, but outliers are identified that combine both a wide band gap and a large refractive index. Focusing on these outliers, we explore the requirements for a wide band gap semiconductor to achieve a large refractive index. Our analysis reveals the importance of the density of states allowing for transitions between the top of the valence and the bottom of the conduction bands. The large availability of states for energy transitions somehow balances the effect of the band gap on the refractive index.