Berlin 2015 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 96: Poster III C (III-V Semiconductors incl. Nitrides)

HL 96.8: Poster

Donnerstag, 19. März 2015, 14:00–20:00, Poster B

Optical investigations on the effect of hydrogen on the internal quantum efficiency of GaInN LED structures — •Silke Wolter, Fedor Alexej Ketzer, Heiko Bremers, Torsten Langer, Uwe Rossow, and Andreas Hangleiter — Institut für Angewandte Physik, Technische Universität Braunschweig

GaInN based light emitting diodes being grown via low pressure MOVPE are investigated regarding the impact of hydrogen from the buffer layer on the active zone. So far hydrogen is used as carrier gas during the growth of the buffer layer. Therefore it is present in the reactor as also in the structure and may influence recombination of carriers and the efficiency of the LED in several ways. Hydrogen is known to influence incorporation as well as electrical activity of defects in GaN.
We compare structures having different surroundings of the quantum well with additional use of hydrogen and silane fluxes during the growth for raising the hydrogen content within the n-GaN buffer layer. The comparison is based on excitation power and temperature dependent photoluminescence (PL) spectroscopy. From the data we determine the internal quantum efficiency and compare it with time-resolved PL measurements to understand the influence of hydrogen on radiative and nonradiative recombination. Our results show that the growth of the layers close to the quantum well highly affects the efficiency of the LED. While low temperature PL shows high intensity, room temperature efficiency is decreased which may be attributed to a change in the density of background carriers.