Projections/depressions forming a two-dimensional periodic structure are
formed in a surface of a semiconductor multilayer film opposing the
principal surface thereof, while a metal electrode with a high
reflectivity is formed on the other surface. By using the diffracting
effect of the two-dimensional periodic structure, the efficiency of light
extraction from the surface formed with the projections/depressions can
be improved. By reflecting light emitted toward the metal electrode to
the surface formed with the projections/depressions by using the metal
electrode with the high reflectivity, the foregoing effect achieved by
the two-dimensional periodic structure can be multiplied.