Electroluminescence and current-voltage measurements of single (In,Ga)N/GaN nanowire light-emitting diodes in the nanowire ensemble

David van Treeck; Johannes Ledig; Gregor Scholz; Jonas Lähnemann; Mattia Musolino; Abbes Tahraoui; Oliver Brandt; Andreas Waag; Henning Riechert; Lutz Geelhaar

doi:10.3762/bjnano.10.117

arXiv · 1908.08863

Electroluminescence and current-voltage measurements of single (In,Ga)N/GaN nanowire light-emitting diodes in the nanowire ensemble

David van Treeck·Johannes Ledig·Gregor Scholz·Jonas Lähnemann·Mattia Musolino·Abbes Tahraoui·Oliver Brandt·Andreas Waag·Henning Riechert·Lutz Geelhaar

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Abstract

We present the combined analysis of the electroluminescence (EL) as well as the current-voltage (I-V) behavior of single, freestanding (In,Ga)N/GaN nanowire (NW) light-emitting diodes (LEDs) in an unprocessed, self-assembled ensemble grown by molecular beam epitaxy. The data were acquired in a scanning electron microscope equipped with a micromanipulator and a luminescence detection system. Single NW spectra consist of emission lines originating from different quantum wells, and the width of the spectra increases with decreasing peak emission energy. The corresponding I-V characteristics are described well by the modified Shockley equation. The key advantage of this measurement approach is the possibility to correlate the EL intensity of a single NW LED with the actual current density in this NW. This way, the external quantum efficiency (EQE) can be investigated as a function of the current in a single NW LED. The comparison of the EQE characteristic of single NWs and the ensemble device allows a quite accurate determination of the actual number of emitting NWs in the working ensemble LED and the respective current densities in its individual NWs. This information is decisive for a meaningful and comprehensive characterization of a NW ensemble device, rendering the measurement approach employed here a very powerful analysis tool.

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David van Treeck, Johannes Ledig, Gregor Scholz, Jonas Lähnemann, Mattia Musolino, Abbes Tahraoui, Oliver Brandt, Andreas Waag, Henning Riechert, Lutz Geelhaar. 2019-08-23. Electroluminescence and current-voltage measurements of single (In,Ga)N/GaN nanowire light-emitting diodes in the nanowire ensemble. https://doi.org/10.3762/bjnano.10.117

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