Modeling Dilute Nitride 1.3 μm Quantum Well Lasers: Incorporation of N Compositional Fluctuations

Compositional fluctuations of N in Ga_0.68In_0.32N_xAs_1-x result in quantum dot (QD)-like fluctuations in the conduction band edge (CBE). The influence of these compositional fluctuations on the performance of Ga _0.68In_0.32 NxAs_1-x /GaAs quantum well (QW) lasers has been studied using a rate equation approach. Adding N into InGaAs has been observed to reduce the photon luminescence (PL) intensity, broaden the line width, and increase the laser threshold. For low N composition (N ≈ 1%), due to the small density of QD-like fluctuations, the electron density within the fluctuations is below the lasing threshold and they act as defect-related nonradiative centers. However, as N increases (N ≥ 2%), the density of the QD-like fluctuations increases allowing lasing to occur from the QD-like fluctuations. The dynamics of the electrons and photons in both the 2-D QW and the QD-like fluctuations are evaluated. In addition, by adding the gain of the QD-like fluctuations and the QW confined level gain, a broad-band material gain results can be exploited in tuneable lasers.