Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 32: Halbleiterlaser I
HL 32.4: Vortrag
Samstag, 5. März 2005, 15:45–16:00, TU P-N202
Laser emission from ultra-small single quantum-well pillar microcavities — •M. Benyoucef1, P. Michler1, J. Wiersig2, F. Jahnke2, M. Kamp3, and A. Forchel3 — 15. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany — 2Institut für Theoretische Physik, Universität Bremen, Postfach 330440, 28334 Bremen, Germany — 3Technische Physik, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
High efficiency and low threshold semiconductor lasers can be achieved through control of spontaneous emission in microcavities [1]. The spontaneous and stimulated emission of pillar microcavities with different lateral diameters (1-4 µm) were investigated by low temperature (T = 4 K) micro-photoluminescence spectroscopy. The pillar microcavity structures consist of an active region of an InGaAs single quantum-well. A GaAs cavity is sandwiched between the bottom and top distributed Bragg reflectors (DBRs), which consist of 22- and 20-period of AlAs/GaAs layers, respectively.
In this work, we report the observation of lasing with low thresholds (12 mW/cm2) and large spontaneous emission factors (β) from optically-pumped small pillar microcavities. For a 1.5 µm diameter pillar, a linewidth of about 0.17 nm is measured bellow the laser threshold, however, above the laser threshold, the linewidth decreases to a value about 0.08 nm and then is approximately constant for higher excitation powers. Using a rate equation model, we estimate the β values. Furthermore, calculated mode structures of the microcavity lasers will be presented.
[1] F. M. Matinaga et al., Appl. Phys. Lett. 62, 443 (1993).