Semiconductor light-emitting device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorKyosuke Kuramoto
Life of this patent
Estimating the term…
Abstract
A semiconductor light-emitting device which exhibits small threshold current, high differential efficiency, and good characteristics, by reducing electrons that overflow an electron barrier, trapping the electrons in an active layer. Of the barrier layers of an active layer, a final barrier layer, which is a barrier layer closest to a p side, is smaller in band gap energy than other barrier layers. Thus, as compared with a case where the final barrier layer has the same band gap energy as that of the other barrier layer, an energy band discontinuity (electron barrier) with an electron blocking layer can be made larger. As a result, overflow of electrons is reduced.
Claims24
A semiconductor light-emitting device comprising:
- an n-type cladding layer and a p-type cladding layer of a nitride-based III-V compound semiconductor material;
- an active layer, sandwiched by said n-type and p-type cladding layers, of a nitride-based III-V compound semiconductor material, wherein
- said active layer includes a plurality of barrier layers, and a plurality of well layers, said well and barrier layers being alternatingly arranged,
- all of said well layers of said active layer have a first bandgap energy that is substantially uniform,
- all of said barrier layers of said active layer have a second bandgap energy that is substantially uniform, and
- said active layer has a first end closer to said n-type cladding layer than to said p-type cladding layer, located adjacent one of said barrier layers, and a second end, closer to said p-type cladding layer than to said n-type cladding layer, and located adjacent one of said well layers;
- a final barrier layer of a nitride-based III-V compound semiconductor material, which, with said active layer, constitutes a multiple quantum well structure, and which is located between the second end of said active layer and said p-type cladding layer, said final barrier layer including at least one layer having a band gap energy that is smaller than the second band gap energy;
- and
- an electron blocking layer of a nitride-based III-V compound semiconductor material including Al and which is located between said final barrier layer and said p-type cladding layer, and which contacts said at least one layer of said final barrier layer having a band gap energy that is smaller than the second band gap energy, wherein
- said p-type cladding layer has a bandgap energy larger than the second bandgap energy, and
- said electron blocking layer has a bandgap energy larger than the bandgap energy of said p-type cladding layer.
A semiconductor light-emitting device comprising:
- an n-type cladding layer and a p-type cladding layer of a nitride-based III-V compound semiconductor material;
- an active layer, sandwiched by said n-type and p-type cladding layers, of a nitride-based III-V semiconductor material, wherein
- said active layer includes a plurality of barrier layers, and a plurality of well layers alternating with said barrier layers,
- all of said well layers of said active layer have a first bandgap energy that is substantially uniform,
- all of said barrier layers of said active layer have a second bandgap energy that is substantially uniform, and
- said active layer has a first end closer to said n-type cladding layer than to said p-type cladding layer, located adjacent one of said barrier layers, and a second end, closer to said p-type cladding layer than to said n-type cladding layer, and located adjacent one of said well layers;
- a first layer of a of a nitride-based III-V compound semiconductor material which is located between the second end of said active layer and said p-type cladding layer, and which has a band gap energy smaller than the second band gap energy and larger than the first band gap energy;
- and
- an electron blocking layer of a nitride-based III-V compound semiconductor material including Al and which is located between said first layer and said p-type cladding layer, contacting said first layer, wherein
- said p-type cladding layer has a bandgap energy larger than the second bandgap energy, and
- said electron blocking layer has a bandgap energy larger than the bandgap energy of said p-type cladding layer.
Dependencies are inferred from the claim text.