Abstract: A semiconductor light-emitting device includes a substrate having a first energy bandgap, a first semiconductor layers on the substrate, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer. The active layer includes a quantum well layer, and a first barrier layer between the first semiconductor layer and the quantum well layer. The first semiconductor layer has a second energy bandgap wider than the first energy bandgap. The quantum well layer has a third energy bandgap narrower than the first and second energy bandgaps. The second semiconductor layer has a fourth energy bandgap wider than the third energy bandgap. The substrate has a refractive index greater than a refractive index of the first semiconductor layer. The refractive index of the first semiconductor layer is not less than a refractive index of the first barrier layer.

Abstract: A semiconductor light-emitting device includes a GaAs (gallium arsenide) substrate of a cubic crystal, a light-emitting layer and a multi-semiconductor layer. The light-emitting layer being provided on the GaAs substrate. The light-emitting layer includes InGaAs (indium gallium arsenide) represented by a compositional formula InxGa1-xAs (0<x<1). The multi-semiconductor layer being provided on a front surface of the GaAs substrate between the GaAs substrate and the light-emitting layer. The multi-semiconductor layer is tilted with respect to a (100) plane of the cubic crystal. The multi-semiconductor layer includes a first layer and a second layer. The first and second layers are alternately stacked in a direction perpendicular to the front surface of the GaAs substrate. The first layer is different in composition from the second layer.

Abstract: A semiconductor light-emitting device includes a substrate having a first energy bandgap, a first semiconductor layers on the substrate, an active layer on the first semiconductor layer, and a second semiconductor layer on the active layer. The active layer includes a quantum well layer, and a first barrier layer between the first semiconductor layer and the quantum well layer. The first semiconductor layer has a second energy bandgap wider than the first energy bandgap. The quantum well layer has a third energy bandgap narrower than the first and second energy bandgaps. The second semiconductor layer has a fourth energy bandgap wider than the third energy bandgap. The substrate has a refractive index greater than a refractive index of the first semiconductor layer. The refractive index of the first semiconductor layer is not less than a refractive index of the first barrier layer.