Electronic structure of image and SnO under pressure Original Research Article

The two semiconductor compounds GaAs1-xNxGaAs1-xNx and SnO are both technologically important due to their optical properties. Dilute GaAs1-xNxGaAs1-xNx (x below 0.02–0.03) are peculiar in the sense that they have band gaps which are smaller than those of both GaN (3.5 eV) and GaAs (1.42 eV), and the gap can be tuned by varying x. We present calculations of gaps and effective masses vs. composition and applied external pressure. The lowest band gap in tin monoxide is indirect, and under pressure the material undergoes an insulator–metal transition. This is examined by theoretical calculations, including structural optimization, and the bonding in SnO is analyzed. The role of the Sn-5s lone pair is examined. Also similarities and differences between SnO and PbO are discussed (relativistic effects).