Berlin 2008 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 45: GaN devices
HL 45.6: Talk
Thursday, February 28, 2008, 10:45–11:00, EW 202
Characteristics of (Al,In,Ga)N multiple quantum well structures for blue-green laser diodes — •Veit Hoiffmann1, Arne Knauer1, Frank Brunner1, Carsten Netzel1, Markus Weyers1, Günther Tränkle1, Tim Kolbe2, Jan Robert van Look2, and Michael Kneissl1,2 — 1Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin — 2Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin
(Al,In,Ga)N based laser diodes (LD) emitting in the violet spectral region are already commercially available with excellent lifetimes and high efficiencies. In order to extend the emission wavelength of these devices towards the blue and green high quality InGaN quantum well structures have to be realized. However, multiple quantum well (MQW) structures with high indium content exhibit low efficiencies, due to the large piezoelectric fields (FPZ) as well as the deterioration in crystal quality. We have investigated the growth of InGaN MQW structures emitting in the blue-green wavelength region with photoluminescence and high resolution X-Ray diffraction. In our studies we were able to determine FPZ quantitatively and show how FPZ is influenced by the barrier composition, e.g. by adding indium to the barriers and by partially doping the barriers with silicon. By increasing the growth temperature G during the barrier growth, we were able to improve the ratio of radiative to non-radiative recombination. Finally, we will discuss the effects of barrier composition and optimized growth conditions on light output and threshold current densities for LDs.