Experimental study of temperature sensitivity of carrier lifetime and recombination coefficients in GaInNAs SQW lasers
This paper deals with the characterization of the differential carrier lifetime and the calculation of the monomolecular, radiative and non-radiative recombination coefficients and their temperature dependence as an evidence of the excellent temperature performance of this material system. The device characterized is a 1.25 /spl mu/m GaInNAs laser structure grown on a GaAs substrate. The active region consists of a single 6 nm thick single quantum well. Light current (L-I) characteristics performed over a temperature range of 20/spl deg/C to 80/spl deg/C, show a characteristic temperature of 50 K. Similar than in the case of commercial InGaAs. Good temperature performance of optical gain using Hakki-Paoli method, lasing wavelength and efficiency will also be presented and compared with modelling work.
Modeling Dilute Nitride 1.3 μm Quantum Well Lasers: Incorporation of N Compositional Fluctuations
Compositional fluctuations of N in Ga0.68In0.32NxAs1-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 0.68In0.32 NxAs1-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.
Explicit solutions for N-dimensional Schrödinger equations with position-dependent mass
With the consideration of spherical symmetry for the potential and mass function, one-dimensional solutions of nonrelativistic Schrodinger equations with spatially varying effective mass are successfully extended to arbitrary dimensions within the frame of recently developed elegant nonperturbative technique, where the BenDaniel-Duke effective Hamiltonian in one dimension is assumed like the unperturbed piece, leading to well-known solutions, whereas the modification term due to possible use of other effective Hamiltonians in one dimension and, together with the corrections coming from the treatments in higher dimensions, are considered as an additional term like the perturbation. Application of the model and its generalization for the completeness are discussed.