Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 27: Nitrides: Preparation and characterization II

HL 27.7: Vortrag

Mittwoch, 14. März 2018, 11:15–11:30, EW 203

MOVPE growth of large area InGaN LEDs with GaN-based tunnel junctions — •Silvio Neugebauer, Christoph Berger, Florian Hörich, Christopher Kahrmann, Jürgen Bläsing, Armin Dadgar, and André Strittmatter — Institut für Experimentelle Physik, Otto-von-Guericke-University Magdeburg, Germany

Improving current injection in nitride-based devices is an important task to further enhance the efficiencies of light emitting devices. One limiting factor is the low hole mobility in Mg-doped GaN which hampers lateral current spreading in conventional p/n-junction devices. In order to maintain high optical output power, non-epitaxial transparent and semi-transparent contact schemes are widely employed to inject holes into the p-side region. Still, the use of such current spreading layers is limited in terms of lateral conductivity and optical transparency. Epitaxial growth of GaN-based p/n tunnel junctions (TJs) structures is an attractive alternative to improve lateral current spreading in LEDs and VCSELs. However, the effectiveness of the MOVPE grown TJ is limited by the achievable donor and acceptor concentrations as well as the activation of the buried Mg-doped layer. In this study we have grown tunnel junction structures on top of conventional LEDs in a single growth process. The influence of thermal activation and individual parameter variations for the n- and p-type doping within the tunnel junction were analyzed in terms of current-voltage characteristics and light output of processed 1 mm² LED devices and compared to the performance of a reference LED with Ni/Au contacts.