Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 24: Nitrides: Preparation and characterization I
HL 24.8: Vortrag
Mittwoch, 3. April 2019, 11:30–11:45, H31
Effect of optimized GaN underlayers on the radiative efficiency of GaInN/GaN quantum wells — •Philipp Horenburg1, Philipp Henning1, Savutjan Sidik1, Uwe Rossow1, Heiko Bremers1,2, and Andreas Hangleiter1,2 — 1Institute of Applied Physics, Technische Universität Braunschweig, Germany — 2Laboratory for Emerging Nanometrology, Braunschweig, Germany
We present the influence of optimized low temperature GaN underlayers on the efficiency of GaInN/GaN quantum well (QW) structures prepared by metal-organic vapor phase epitaxy (MOVPE).
As light emission from group-III nitride QW structures is governed by radiative and nonradiative processes, the active region is highly susceptible to structural defects, acting as nonradiative recombination centers and therefore diminishing the radiative efficiency. Insertion of a low indium content GaInN underlayer prior to the QW structure has become a widely used strategy to bury crystallographic defects outside the active region. In this context, the In atoms have been ascribed to play a special role in the defect trap mechanism.
We have grown a series of c-plane single and multiple QW structures by low-pressure MOVPE on sapphire and GaN substrates. By introducing a GaN pre-barrier prior to the GaInN/GaN QWs and optimizing the growth conditions of the former, we find improved efficiency as observed by photoluminescence measurements. Thus, we argue that not merely the material composition of the underlayer, but particularly the growth parameters, such as the temperature and the precursor fluxes, crucially affect the efficiency of GaInN/GaN QW structures.