An LED includes a semiconductor region having an active layer sandwiched
between two confining layers of opposite conductivity types for
generating heat. A cathode is arranged centrally on one of the opposite
major surfaces of the semiconductor region from which is emitted the
light. Attached to the other major surface of the semiconductor region,
via an ohmic contact layer, is a reflective metal layer for reflecting
the light that has traversed the ohmic contact layer, back toward the
semiconductor region. A transparent antidiffusion layer is interposed
between the ohmic contact layer and the reflective layer in order to
prevent the ohmic contact layer and the reflective layer from thermally
diffusing from one into the other to the impairment of the reflectivity
of the reflective layer.