The temperature dependence of 1.3- and 1.5-Μm compressivelystrained InGaAs(P) MQW semiconductor lasers

摘要

We have studied experimentally and theoretically the spontaneousnemission from 1.3- and 1.5-Μm compressively strained InGaAsPnmultiple-quantum-well lasers in the temperature range 90-400 K tondetermine the variation of carrier density n with current I up tonthreshold. We find that the current contributing to spontaneous emissionnat threshold IRad is always well behaved and has ancharacteristic temperature T0 (IRad)≈T, asnpredicted by simple theory. This implies that the carrier density atnthreshold is also proportional to temperature. Below a breakpointntemperature TB, we find I Α nZ, where Z=2.nAnd the total current at threshold Ith also has ancharacteristic temperature T0 (Ith)≈T, showingnthat the current is dominated by radiative transitions right up tonthreshold. Above TB, Z increases steadily to Z≈3 andnT0 (Ith) decreases to a value less than T/3. Thisnbehavior is explained in terms of the onset of Auger recombination abovenTB; a conclusion supported by measurements of the pressurendependence of Ith. From our results, we estimate that, at 300nK, Auger recombination accounts for 50% of Ith in then1.3-Μm laser and 80% of Ith in the 1.5-Μm laser.nMeasurements of the spontaneous emission and differential efficiencynindicate that a combination of increased optical losses and carriernoverflow into the barrier and separate confinement heterostructurenregions may further degrade T0 (Ith) above roomntemperature