Growth temperature dependence of optical modal gain and loss in GaN:Eu active medium on Si.

The dependence of optical modal gain and loss on GaN:Eu growth temperature is reported. GaN:Eu thin films were grown on Si substrates with AlGaN transition and cladding layers at temperatures ranging from 600 degrees C to 850 degrees C. The modal gain and loss in the GaN:Eu layer were a strong function of the optically active Eu atomic concentration and of the interface quality between the active layer and the top cladding layer, which in turn depended on the growth temperature. Optimum optical properties of maximum modal gain of ~ 100 cm(-1) and minimum loss of ~ 46 cm(-1) were obtained for growth at 800 degrees C.