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InAs quantum-dot (QD) lasers were investigated in the temperature range 20-300 K and under hydrostatic pressure in the range of 0-12 kbar at room temperature. The results indicate that Auger recombination is very important in 1.3-μm QD lasers at room temperature and it is, therefore, the possible cause of the relatively low characteristic temperature observed, of T0=41K. In the 980-nm QD lasers where T0=110-130 K, radiative recombination dominates. The laser emission photon energy Elas increases linearly with pressure p at 10.1 and 8.3 meV/kbar for 980 nm and 1.3-μm QD lasers, respectively. For the 980-nm QD lasers the threshold current increases with pressure at a rate proportional to the square of the photon energy E2las. However, the threshold current of the 1.3-μm QD laser decreases by 26% over a 12-kbar pressure range. This demonstrates the presence of a nonradiative recombination contribution to the threshold current, which decreases with increasing pressure. The authors show that this nonradiative contribution is Auger recombination. The results are discussed in the framework of a theoretical model based on the electronic structure and radiative recombination calculations carried out using an 8×8 k·p Hamiltonian.
Selected Topics in Quantum Electronics, IEEE Journal of (Volume:9 , Issue: 5 )
Date of Publication: Sept.-Oct. 2003