Semiconductor light emitting device

摘要

According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer, a second semiconductor layer, a light emitting part, and a multilayered structural body. The light emitting part is provided between the first and second semiconductor layers and includes barrier layers and well layers alternately stacked. The multilayered structural body is provided between the first semiconductor layer and the light emitting part and includes high energy layers and low energy layers alternately stacked. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the multilayered structural body. An average In composition ratio on a side of the second semiconductor is higher than that on a side of the first semiconductor in the light emitting part.

主权项

1. A semiconductor light emitting device comprising:
a first semiconductor layer of n-type conductivity including a nitride semiconductor; a second semiconductor layer of p-type conductivity including a nitride semiconductor; a light emitting part provided between the first semiconductor layer and the second semiconductor layer, the light emitting part including a plurality of barrier layers and a plurality of well layers alternately stacked with the barrier layers, the barrier layers including a nitride semiconductor, the well layers including a nitride semiconductor and having a band gap energy lower than a band gap energy of the barrier layers; and a multilayered structural body provided between the first semiconductor layer and the light emitting part, the multilayered structural body including a plurality of high energy layers and a plurality of low energy layers alternately stacked with the high energy layers, the high energy layers including a nitride semiconductor, the low energy layers including a nitride semiconductor and having a band gap energy lower than a band gap energy of the high energy layers, one of the high energy layers having an In composition ratio xa among group III elements and a layer thickness to (nanometers), one of the low energy layers in contact with the one of the high energy layers having an In composition ratio xb among group III elements and a layer thickness tb (nanometers), other one of the high energy layers located closer to the second semiconductor layer than the one of the high energy layers having an In composition ratio xc among group III elements and a layer thickness tc (nanometers), other one of the low energy layers in contact with the other one of the high energy layers having an In composition ratio xd among group III elements and a layer thickness td (nanometers), the xd being different from the xb, SA2=(xc·tc+xd·td)/(tc+td) being higher than SA1=(xa·ta+xb·tb)/(ta+tb), one of the barrier layers having an In composition ratio ya among group III elements and a layer thickness sa (nanometers), one of the well layers in contact with the one of the barrier layers having an In composition ratio yb among group III elements and a layer thickness sb (nanometers), other one of the barrier layers located closer to the second semiconductor layer than the one of the barrier layers having an In composition ratio yc among group III elements and a layer thickness sc (nanometers), other one of the well layers in contact with the other one of the barrier layers having an In composition ratio yd among group III elements and a layer thickness sd (nanometers), the yd being different from the yb, EA2=(yc·sc+yd·sd)/(sc+sd) being higher than EA1=(ya·sa+yb·sb)/(sa+sb), EA1 being higher than SA2, SR being SA2/SA1, ER being EA2/SA1, and the SR and the ER are located in an area in a coordinate system having a horizontal axis of the SR and a vertical axis of the ER, the area being surrounded by a first linear line, a second linear line and a third linear line, the first linear line connecting a first point and a second point, the second linear line connecting the first point and a third point, the third linear line connecting the second point and the third point, the SR being 1.8 and the ER being 3 at the first point, the SR being 1.8 and the ER being 4 at the second point, the SR being 2.8 and the ER being 4.9 at the third point.