Mitsubishi Denki Kabushiki Kaisha

Tsuneo Okada

Tetsuya Yagi

An AlGaAs/GaAs system light emitting device includes a GaAs substrate doped with a first conductivity type impurity, a first conductivity type Al.sub.y Ga.sub.1-y As first cladding layer, an Al.sub.x Ga.sub.1-x As (0 &lt;x&lt;y) active layer, and an Al.sub.y Ga.sub.1-y As second cladding layer having a second conductivity type opposite to the first conductivity type successively disposed on the substrate. The light emitting device includes an Al.sub.z Ga.sub.1-z As (z.gtoreq.0) buffer layer which is disposed between the GaAs substrate and the first cladding layer containing a dopant impurity in such a high concentration that the intensity of photoluminescent light generated due to the band-to-band transitions is reduced and has a smaller energy band gap than the energy of the light emitted from the light emitting device. Therefore, a long lifetime semiconductor light emitting device having no sub peak in the light emission spectrum can be easily produced with good yield.

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Itami, Japan

Tsuneo Okada