GaN nanowires grown by molecular beam epitaxy generally suffer from dominant nonradiative recombination, which is believed to originate from point defects. To suppress the formation of these defects, we explore the synthesis of GaN nanowires at temperatures up to 915 °C enabled by the use of thermally stable TiNx/Al2O3 substrates. These samples exhibit indeed bound exciton decay times approaching those measured for state-of-the-art bulk GaN. However, the decay time is not correlated with the growth temperature, but rather with the nanowire diameter. The inverse dependence of the decay time on diameter suggests that the nonradiative process in GaN nanowires is not controlled by the defect density, but by the field ionization of excitons in the radial electric field caused by surface band bending. We propose a unified mechanism accounting for nonradiative recombination in GaN nanowires of arbitrary diameter.

Auzelle, T., Azadmand, M., Flissikowski, T., Ramsteiner, M., Morgenroth, K., Stemmler, C., et al. (2021). Enhanced Radiative Efficiency in GaN Nanowires Grown on Sputtered TiNx: Effects of Surface Electric Fields. ACS PHOTONICS, 8(6), 1718-1725 [10.1021/acsphotonics.1c00224].

Enhanced Radiative Efficiency in GaN Nanowires Grown on Sputtered TiNx: Effects of Surface Electric Fields

Azadmand M.;Sanguinetti S.;
2021

Abstract

GaN nanowires grown by molecular beam epitaxy generally suffer from dominant nonradiative recombination, which is believed to originate from point defects. To suppress the formation of these defects, we explore the synthesis of GaN nanowires at temperatures up to 915 °C enabled by the use of thermally stable TiNx/Al2O3 substrates. These samples exhibit indeed bound exciton decay times approaching those measured for state-of-the-art bulk GaN. However, the decay time is not correlated with the growth temperature, but rather with the nanowire diameter. The inverse dependence of the decay time on diameter suggests that the nonradiative process in GaN nanowires is not controlled by the defect density, but by the field ionization of excitons in the radial electric field caused by surface band bending. We propose a unified mechanism accounting for nonradiative recombination in GaN nanowires of arbitrary diameter.
Articolo in rivista - Articolo scientifico
band bending; exciton decay; field ionization; internal quantum efficiency; metallic substrate; molecular beam epitaxy; nitrides; nonradiative recombination;
English
1718
1725
8
Auzelle, T., Azadmand, M., Flissikowski, T., Ramsteiner, M., Morgenroth, K., Stemmler, C., et al. (2021). Enhanced Radiative Efficiency in GaN Nanowires Grown on Sputtered TiNx: Effects of Surface Electric Fields. ACS PHOTONICS, 8(6), 1718-1725 [10.1021/acsphotonics.1c00224].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/319694
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