Electronic Band Structure and Material Gain of Dilute Nitride Quantum Wells Grown on InP Substrate

The eight-band kp Hamiltonian is applied to calculate electronic band structure and material gain in dilute nitride quantum wells (QWs) grown on InP substrate. Three N-containing QW materials (GaInNAs, GaNAsSb, and GaNPSb) and different N-free barriers (GaInAs, GaAsSb, GaPSb, AlGaInAs, GaInPAs, AlGaAsSb, GaPAsSb, and AlGaPSb) lattice matched to InP are analyzed. It is shown that Ga
_0.17
In
_0.83
N
_y
As
_1-y
-QWs with Ga
_0.47
In
_0.53
As, Al
_0.23
Ga
_0.24
In
_0.53
As, or Ga
_0.17
In
_0.83
P
_0.63
As
_0.37
barriers are a very good gain medium for long-wavelength lasers grown on InP substrates. For N-free QWs the transverse electric (TE) mode of the material gain develops at 2.1 μm. This gain peak shifts toward longer wavelengths upon the incorporation of nitrogen and reaches the wavelength of ~2.8 Mm for 3% N. For GaN
_y
As
_0.26-y
Sb
_0.74
-QWs no quantum confinement or very weak quantum confinement exist for electrons in N-free QWs with the ternary barrier (i.e., GaAs
_0.51
Sb
_0.49
) and quaternary (Al
_0.23
Ga
_0.77
As
_0.51
Sb
_0.49
and GaP
_0.25
As
_0.15
Sb
_0.60
) barriers, respectively. However, the quantum confinement in the conduction band strongly increases after incorporation of nitrogen. For GaN
_y
As
_0.26-y
Sb
_0.74
-QWs with 3% N gain peak for TE mode exists at 3.2 μm. Very similar changes in electronic band structure and material gain are noticed for GaN
_y
P
_0.26-y
Sb
_0.74
-QWs with GaP
_0.35
Sb
_0.65
, Al
_0.23
Ga
_0.77
As
_0.52
Sb
_0.48
, and GaP
_0.25
As
_0.15
Sb
_0.60
barriers. In that case gain peak (TE mode) for GaN
_0.03
P
_0.23
Sb
_0.74
-QW with GaP
_0.35
Sb
_0.65
barrier is at 3.6 μm. The intensity and the shape of material gain spectra in the three QW system vary with changes of the nitrogen concentration and the barrier content. At carrier concentration of 5 × 10
¹⁸
cm
^-3
, the largest material gain exists for Ga
_0.17
In
_0.83
N
_y
As
_1-y
-QWs with Al
_0.23
Ga
_0.24
In
_0.53
As and Ga
_0.17
In
_0.83
As
_0.37
Ga
_0.63
barriers.