Ultraviolet emission efficiencies of AlxGa1−xN films pseudomorphically grown on AlyGa1−yN template (x<y) with various Al-content combinations

Abstract: The effect of alloying and expitaxial mismatch strain on the surface ultraviolet (UV) emission efficiencies of AlxGa1−xN films, pseudomorphically grown on both c- and m-plane AlyGa1−yN templates (x<y) for various Al-content combinations, has been investigated under the framework of k·p perturbation theory. The results indicate that the film/template Al-content combination with y>−0.03+1.79x−0.06x2 (0<x<y<1) for the c-plane case and the film/template with all y:x (0<x<y<1) combinations for the m-plane case, are particularly suitable for obtaining efficient UV light emissions. In the latter case, it''s also ideal for fabricating edge-emitting UV devices with predominant transverse electric mode. Furthermore, polarized emissions with high polarization degree can be achieved by properly tuning the y:x ratio for certain x. [Copyright &y& Elsevier]