1. Electroluminescence and current-voltage measurements of single (In,Ga)N/GaN nanowire light-emitting diodes in the nanowire ensemble
- Author
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van Treeck, David, Ledig, Johannes, Scholz, Gregor, Lähnemann, Jonas, Musolino, Mattia, Tahraoui, Abbes, Brandt, Oliver, Waag, Andreas, Riechert, Henning, and Geelhaar, Lutz
- Subjects
Physics - Applied Physics ,Condensed Matter - Materials Science - 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.
- Published
- 2019
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