Anti-localisation suppresses nonradiative recombination in GaInN/GaN quantum wells

Andreas Hangleiter (1) , Carsten Netzel (2) , Daniel Fuhrmann (2) , Frank Ferdinand Hitzel (2) , Lars Hoffmann (2) , Heiko Bremers (2) , Uwe Rossow (2) , George Ade (3) , Peter Hinze (3)

1 Institute of Applied Physics
2 Institute of Applied Physics [Braunschweig]
3 PTB - Physikalisch-Technische Bundesanstalt [Braunschweig]

The light emission efficiency of (AlGaIn)N heterostructures and light emitting diodes is exceptionally high, despite the high density of threading dislocations generally found in such structures. It has become common to attribute the high efficiency to compositional fluctuations or even phase separation in the active GaInN quantum well region. The resulting localization of charge carriers is thought to keep them from recombining nonradiatively at the defects. Here, we show that carriers are mobile at room temperature rather than localized and that under suitable growth conditions hexagonal V-shaped pits decorating the defects exhibit narrow sidewall quantum wells with an effective bandgap significantly larger than that of the regular c-plane quantum wells. Thereby nature provides a unique, hitherto unrecognized mechanism generating a potential landscape which effectively screens the defects themselves by providing an energy barrier around every defect. Thus even for mobile charge carriers nonradiative recombination is effectively suppressed leading to the unexpectedly high emission efficiency.

Mots clés: Physical Sciences

Andreas Hangleiter, Carsten Netzel, Daniel Fuhrmann, Frank Ferdinand Hitzel, Lars Hoffmann, et al.. Anti-localisation suppresses nonradiative recombination in GaInN/GaN quantum wells. Philosophical Magazine, 2007, 87 (13), pp.2041-2065. ⟨10.1080/14786430701199663⟩. ⟨hal-00513817⟩