LIGHT EMITTING DIODE AND SEMICONDUCTOR LASER
An ultraviolet-light-emitting semiconductor diode comprising an n-type ZnO layer with luminous characteristics formed on a transparent substrate, and a p-typ e semiconductor layer selected from the group consisting of SrCu2O2, CuAlO2 an d CuGaO2, which is formed on the n-type ZnO layer to provide a p-n juncti on therebetween. The transparent substrate is preferably a single crystal substrate having atomically flat yttria-stabilized zirconia (YSZ) (III) surface. The n - type ZnO layer is formed on the transparent substrate having a temperature of 200 to 1200.degree.C, and the p-type semiconductor layer selected from the group of SrCu2O2, CuAlO 2 and CuGaO2 is formed on the n-type ZnO layer. The n-type ZnO layer may be form ed without heating the substrate, and then the surface of the ZnO layer may be irradiated with ultraviolet light to promote crystallization therein.