Light-emitting semiconductor device producing red wavelength optical radiation

A light-emitting semiconductor device, comprising:

• a semiconductor substrate;
• an active layer provided above said semiconductor substrate, said active layer producing a red optical radiation;
• a cladding layer provided above said semiconductor substrate adjacent to said active layer;
• and
• an optical waveguide layer interposed between said active layer and said cladding layer,
• said active layer comprising a single quantum well layer of a III-V material in the system of AlGaInPAs having a composition represented as (AlxGa1−x)αIn1−αPtAs1−t (0x≦1, 0<α≦1, 0≦t≦1),
• said cladding layer containing Al and comprising a III-V material in the system of AlGaInPAs having a composition represented as (AlyGa1−y)βIn1−βPvAs1−v (0<y≦1, 0.5<β≦1, 0<v≦1), said cladding layer having a bandgap larger than a bandgap of said active layer and a lattice constant intermediate between a lattice constant of GaP and a lattice constant of GaAs,
• said optical waveguide layer comprising a III-V material in the system of AlGaInPAs having a composition represented as (AlzGa1−z)γIn1−γPuAs1−u (0≦z<1, 0.5<γ≦1, 0<u≦1), said optical waveguide layer having a bandgap larger than said bandgap of said active layer but smaller than said bandgap of said cladding layer.

A light-emitting semiconductor device, comprising:

• a semiconductor substrate;
• an active layer provided above said semiconductor substrate, said active layer producing a red optical radiation;
• a cladding layer provided above said semiconductor substrate adjacent to said active layer;
• and
• an optical waveguide layer interposed between said active layer and said cladding layer,
• said active layer having a multiple quantum well structure comprising a plurality of quantum well layers of a III-V material in the system of AlGaInPAs having a composition represented as (Alx1Ga1−x)α1In1−α1Pt1As1−t1 (0≦x1<1, 0<α1≦1, 0≦t1≦1) and a plurality of barrier layers of a III-V material in the system of AlGaInPAs having a composition represented as (Alx2Ga1−x2) α2In1−α2Pt2As1=t2 (0≦x2<1, 0<α2<1, 0≦t2≦1), each of said barrier layers having a bandgap larger than a bandgap of said quantum well layer,
• said cladding layer containing Al and comprising a III-V material in the system of AlGaInPAs having a composition represented as (AlyGa1−y)βIn1−αPvAs1−v (0<y≦1, 0.5<β≦1, 0<v≦1), said cladding layer having a bandgap larger than a bandgap of said quantum well layer in said active layer and a lattice constant intermediate between a lattice constant of GaP and a lattice constant of GaAs,
• said optical waveguide layer comprising a III-V material in the system of AlGaInPAs having a composition represented as (AlzGa1−z)γIn1−γPuAs1−u (0≦z<1, 0.5<γ≦1, 0<u≦1), said optical waveguide layer having a bandgap larger than said bandgap of said quantum well layer in said active layer but smaller than said bandgap of said cladding layer.

A laser diode, comprising:

• a semiconductor substrate;
• a first cladding layer of AlGaInP provided above said semiconductor substrate, said first cladding layer having a first conductivity type and a lattice constant intermediate between a lattice constant of GaAs and a lattice constant of GaP;
• an active layer of GaInPAs provided above said first cladding layer;
• a second cladding layer of AlGaInP provided above said active layer, said second cladding layer having a second conductivity type and a lattice constant substantially identical with said lattice constant of said first cladding layer;
• an etching stopper layer of GaInP provided above said second cladding layer, said etching stopper layer having said second conductivity type;
• a third cladding layer of AlGaInP provided above said etching stopper layer, said third cladding layer having said second conductivity type and a lattice constant substantially identical with said lattice constant of said first cladding layer:
• said etching stopper layer having a lattice constant generally equal to said lattice constant of said first cladding layer and a bandgap substantially larger than a bandgap of said active layer.

A light-emitting semiconductor device, comprising:

• a semiconductor substrate;
• a first cladding layer of n-type AlGaInP provided above said semiconductor substrate, said first cladding layer having a composition represented as (Alx1Ga1−x1)y1In1−y1P (0<x1≦1, 0.51<y1≦1) and a lattice constant intermediate between a lattice constant of GaAs and a lattice constant of GaP;
• an active layer provided above said first cladding layer;
• a second cladding layer of p-type AlGaInP provided above said active layer, said second cladding layer having a composition substantially identical with said composition of said first cladding layer;
• wherein a multiple quantum barrier structure is interposed between said active layer and said second cladding layer,
• said multiple quantum barrier structure comprising an alternate repetition of a quantum well layer having a composition represented as (Alx2Ga1−x2)y2In1−y2P (0≦x2≦1, 0≦y1≦1) and a bandgap smaller than a bandgap of said second cladding layer, and a barrier layer having a composition substantially identical with said composition of said second cladding layer.

A light-emitting semiconductor device, comprising:

• a semiconductor substrate;
• a first cladding layer of n-type AlGaInP provided above said semiconductor substrate, said first cladding layer having a composition represented as (Alx1Ga1−x1)y1In1−y1P (0≦x1≦1, 0.51<y1≦1) and a lattice constant intermediate between a lattice constant of GaAs and a lattice constant of GaP;
• an active layer provided above said first cladding layer;
• a second cladding layer of p-type AlGaInP provided above said active layer, said second cladding layer having a composition substantially identical with said composition of said first cladding layer;
• wherein a carrier blocking layer is interposed at least between said active layer and said second cladding layer, said carrier blocking layer having a composition represented as (Alx3Ga1−x3)y1In1−y1P (0≦x1≦x3≦1, 0.51<y1≦1) and a bandgap larger than a bandgap of said second cladding layer, said carrier blocking layer having a lattice constant generally matching with a lattice constant of said second cladding layer.

A light-emitting semiconductor device, comprising:

• a semiconductor substrate;
• a first cladding layer of n-type AlGaInP provided above said semiconductor substrate, said first cladding layer having a composition represented as (Alx1Ga1−x1)y1In1−y1P (0≦x1≦1, 0.51<y1≦1) and a lattice constant intermediate between a lattice constant of GaAs and a lattice constant of GaP;
• an active layer provided above said first cladding layer;
• a second cladding layer of p-type AlGaInP provided above said active layer, said second cladding layer having a composition substantially identical with said composition of said first cladding layer;
• wherein a carrier blocking layer is interposed at least between said active layer and said second cladding layer, said carrier blocking layer having a composition represented as (Alx4Ga1−x4)y4In1−y4P (0≦x4≦1, 0.51<y1<y4 ≦1) and a bandgap larger than a bandgap of said second cladding layer, said carrier blocking layer having a lattice constant smaller than a lattice constant of said second cladding layer.