AlGaN/AlN Stranski–Krastanov Quantum Dots for Highly Efficient Electron Beam-Pumped Emitters: The Role of Miniaturization and Composition to Attain Far UV-C Emission - Archive ouverte HAL Access content directly
Journal Articles ACS photonics Year : 2023

AlGaN/AlN Stranski–Krastanov Quantum Dots for Highly Efficient Electron Beam-Pumped Emitters: The Role of Miniaturization and Composition to Attain Far UV-C Emission

Abstract

Conventional ultraviolet lamps for disinfection emit radiation in the 255–270 nm range, which poses a high risk of causing cancer and cataracts. To address these concerns, solid-state UV-C sources emitting below 240 nm are attractive as a safe and sustainable disinfection solution for occupied spaces. This article delves into the extension of AlxGa1–xN/AlN quantum dot (QD) technology toward the far UV-C range. The structural and optical impact of increasing the Al content in the QDs through the increase of the Al flux and eventual correction of the Ga flux, and the effect of extreme miniaturization of the QDs achieved by reducing their growth time, are explored. The internal quantum efficiency of self-assembled QDs, grown with a metal/N ratio ranging from 0.5 to 0.8, remains around 50% regardless of the Al content (up to 65%) or emission wavelength (300–230 nm). However, QDs emitting below 270 nm display bimodal luminescence due to inhomogeneous in-plane emission caused by fluctuations in the QD shape linked to extended defects. Reducing the QD size exacerbates this bimodality without altering the emission wavelength. Power efficiencies under electron beam pumping range from 0.4 to 1%, with the potential for improvement through surface treatments enhancing light extraction efficiency.

Dates and versions

hal-04274445 , version 1 (07-11-2023)

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Jesus Cañas, Anjali Harikumar, Stephen Purcell, Nevine Rochat, Adeline Grenier, et al.. AlGaN/AlN Stranski–Krastanov Quantum Dots for Highly Efficient Electron Beam-Pumped Emitters: The Role of Miniaturization and Composition to Attain Far UV-C Emission. ACS photonics, 2023, 10 (12), pp.4225-4235. ⟨10.1021/acsphotonics.3c00948⟩. ⟨hal-04274445⟩
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