Current Crowding in a High-Efficiency Black Phosphorus Light-Emitting Diode Using a Reflective Back Contact
Abstract
We demonstrate a high-performance mid-infrared (MIR) light-emitting diode (LED) based on a black phosphorus (b-P)/n-MoS heterojunction. A gold back contact combined with a rhenium-doped n-type MoS layer is used to enhance light extraction. The device shows a MIR peak external quantum efficiency (EQE) of (1.6 0.2) % at room temperature and a record (7.0 0.5) % EQE at 77 K, with a maximum radiant power density of (108 8) W/cm2. Finite-element simulations highlight the importance of phonon-assisted band-to-band tunneling under reverse bias and the influence of carrier velocity saturation under forward bias. The simulations also reveal that the high ideality factors extracted from the current-voltage characteristic are due to current crowding at the heterojunction and a consequence of the device geometry. These findings establish a new high-performance b-P LED architecture and provide crucial insights into the physics of MIR sources based on 2D materials.
Keywords
Cite
@article{arxiv.2506.09835,
title = {Current Crowding in a High-Efficiency Black Phosphorus Light-Emitting Diode Using a Reflective Back Contact},
author = {Julien Brodeur and Éloïse Rahier and Mathieu Chartray-Pronovost and Étienne Robert and Oussama Moutanabbir and Stéphane Kéna-Cohen},
journal= {arXiv preprint arXiv:2506.09835},
year = {2025}
}