Dresden 2011 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 76: Nitride-based Green Lasers
HL 76.2: Talk
Thursday, March 17, 2011, 12:00–12:15, POT 51
The loss mechanisms in green-emitting laser diodes — •Andreas Kruse1, Moritz Brendel1, Uwe Rossow1, Hyonju Chauveau2, Jean-Yves Duboz2, and Andreas Hangleiter1 — 1Institut für Angewandte Physik, TU Braunschweig — 2CRHEA-CNRS, Valbonne, France
While GaInN violet-blue laser diodes with high output power and long lifetimes are already commercially available, strong decrease in power performance by extending the emission wavelength beyond to 500 nm is observed. The aim of our investigations is to understand the limits of optical gain for green-emitting LDs. For this purpose we carried out optical gain measurements by using the variable stripe length method on laser structures grown on c-plane sapphire and GaN bulk substrates, in which various parameters such as number and thickness of quantum well(QW) as well as indium content in QW up to ca. 30% were varied. We focus our studies on two aspects: (1) the impact of defects on gain amplitude as well as inhomogeneous broadening of the gain spectra and (2) the influence of AlInN and AlGaN lower cladding layers on the optical confinement properties due to their different refractive index contrast. Our SQW laser structures emitting at longer wavelength show a net optical gain with internal optical losses smaller than 30cm−1. Moreover, an increase of the inhomogeneous broadening with increasing number of QWs is observed. For the laser structures with AlInN as lower cladding layer very high net optical gain is achieved compared to those with AlGaN cladding layers.