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27 April 2010 Turn-on delay and Auger recombination in long-wavelength vertical-cavity surface-emitting lasers
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Auger recombination plays an important role in lasers operating in the long-wavelength regime (> 1 μm). Indeed, the Auger recombination time decreases exponentially with the inverse of the band gap energy and with temperature. A frequently used technique to estimate the Auger coefficient is the turn-on delay experiment, in which the time delay between the current pulse and the laser light pulse is evaluated. We reviewed the theory behind this experiment and found a discrepancy of the standard formulae used in the literature. This discrepancy occurs due to the assumption that the differential recombination time is independent of the carrier density, which is generally not justified. In particular, for short-wavelength lasers, it is expected that bimolecular recombination dominates, whereas for long-wavelength lasers, Auger recombination dominates. These two contributions can lead to additional linear and quadratic dependences of the differential recombination time on the carrier density. A general formula for the turn-on delay is thus derived, which explicitly includes capture, radiative and Auger recombination mechanisms. Analytical details for using this formula are given and it is shown how it reduces when a particular recombination process dominates. Estimations for the different recombination coefficients are found by fitting experimental data with the formula derived. This procedure is then applied to the case of long-wavelength vertical-cavity surface-emitting lasers (VCSELs) that incorporate InAlGaAs/InP systems in their active region.
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N. Volet and E. Kapon "Turn-on delay and Auger recombination in long-wavelength vertical-cavity surface-emitting lasers", Proc. SPIE 7720, Semiconductor Lasers and Laser Dynamics IV, 772009 (27 April 2010);

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