Semiconductor light emitting diode

A semiconductor light emitting diode comprising a compound semiconductor substrate and a double-hetero structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0.ltoreq.x.ltoreq.1.0<y<1) as an active layer sandwiched between upper and lower clad layers, the band gap energy of the upper clad layer gradually decreasing with increasing distance from a light emitting side of the active layer, wherein the band gap energy of the upper clad layer is at least 0.2 eV larger than that of the active layer at a distance 0.5 .mu.m from its interface with the active layer.

A semiconductor light emitting diode comprising compound semiconductor substrate and a double-hetero structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0.ltoreq.x.ltoreq.1.0<y<1) as an active layer sandwiched between upper and lower clad layers, the band gap energy of the upper clad layer gradually decreasing with increasing distance from a light emitting side of the active layer, wherein the upper clad layer has a thickness of 5-10 .mu.m.

A semiconductor light emitting diode comprising compound semiconductor substrate and a double-hetero structure of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P (0.ltoreq.x.ltoreq.1.0<y<1) as an active layer sandwiched between upper and lower clad layers, carrier concentration of the upper clad layer gradually increasing with increasing distance from a light emitting side of the active layer, wherein the upper clad layer has a thickness of 5-10 .mu.m.