ISSN 1062-8738, Bulletin of the Russian Academy of Sciences. Physics, 2012, Vol. 76, No. 2, pp. 211–213. © Allerton Press, Inc., 2012. Original Russian Text © L.E. Vorobjev, D.A. Firsov, M.Ya. Vinnichenko, V.L. Zerova, G.A. Melentyev, M.O. Mashko, L. Shterengas, G. Kipshidze, G. Belenky, T. Hosoda, 2012, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2012, Vol. 76, No. 2, pp. 240–242. 211 This work is aimed at investigating the carrier recombination processes in InGaAsSb/AlGaAsSb quantum-well (QW) nanostructures. The injection laser diodes based on such structures emit radiation in the wavelength range between two and three μm and above. At high injection levels, the Auger recombina- tion is one of the most important mechanisms of non- radiative recombination in QWs. In some cases, Auger recombination can become resonant, which shortens the nonradiative lifetime by 2–3 orders of magnitude [1] and causes corresponding worsening the laser parameters. For these reasons, the investigation of Auger recombination is undoubtedly of interest. Here, we study the dynamics of photoluminescence (PL) in In 0.53 Ga 0.47 As 0.24 Sb 0.76 /Al 0.7 Ga 0.3 As 0.056 Sb 0.944 semiconductor structures containing ten QWs. The structures differed by their quantum well widths: 4, 5, 6, 7 and 8 nm. The time evolution of the photolumi- nescence induced when e–h pairs were excited by 150 fs pulses was studied in the pico- and nanosecond ranges by means of up-conversion technique. The rep- etition rate of the pump laser radiation was 100 MHz, and its photon energy was hν ex = 1.17 eV. According to our calculations, at this photon energy electrons in QW of 5-, 6-, 7- or 9-nm width are injected not only in the e1 subband (transitions hh1 → e1) but also in the e2 subband (transitions hh2 → e2), as shown in Fig. 1. Note that due to the low thickness of the QW-forming layers, the concentration of e–h pairs excited in the QW is low compared to that in the case of carrier exci- tation in a waveguide [2]. Our goal was to investigate the contribution of Auger processes, in particular, resonance Auger recombination to carrier recombination processes. Resonance Auger recombination is considerable in quantum wells where the energy difference between the second e2 and the first e1 levels of dimensional quanti- zation of electrons is approximately equal to the energy difference between the first level of electrons e1 and the first level of heavy holes hh1; E(e2) – E(e1) = E(e1) – E(hh1) (see Fig. 1). We studied a number of structures expecting to observe the resonance Auger recombina- tion in one with a quantum well width of 6 nm. The intensity of photoluminescence at the peak of its spectral dependence is determined by optical tran- sitions of electrons between energy states near the bot- tom of the electronic e1 subband and the top of the hh1 Influence of Auger Recombination on the Lifetime of Nonequilibrium Carriers in InGaAsSb/AlGaAsSb Quantum Well Structures L. E. Vorobjev a , D. A. Firsov a , M. Ya. Vinnichenko a , V. L. Zerova a , G. A. Melentyev a , M. O. Mashko a , L. Shterengas b , G. Kipshidze b , G. Belenky b , and T. Hosoda b a St. Petersburg State Polytechnical University, St. Petersburg, 195251 Russia b SUNY, Stony Brook, NY 11794, USA e-mail: lvor@rphf.spbstu.ru; mvin@spbstu.ru Abstract—Carrier recombination processes, including the Auger recombination, are studied in InGaAsSb/AlGaAsSb quantum well nanostructures. Based on the dynamics of photoluminescence, we esti- mate the emission time of an optical phonon, determined the recombination rate as a function of optical-exci- tation intensity, and estimated the coefficient characterizing the rate of the resonance Auger recombination. DOI: 10.3103/S1062873812020104 1200 0 –200 –400 –600 1.0 × 10 7 0 200 400 600 800 1000 –1.0 × 10 7 k, cm –1 350 300 250 200 150 100 z, Å Energy, meV hν ex = 1.17 eV hν ex = 1.17 eV 538 meV 530 meV hν hh1 hh2 e1 e2 Fig.1. Energy band diagram for the 590-6 nm structure (calculated for Т = 77 K) with a quantum well width of 6 nm. Dashed arrows indicate the process close to the res- onance Auger process.