Localized Excitonic Emission in Wafer-Scale MOCVD-Grown GaSe 2D Nanosheets for Classical and Non-Classical Light Sources

Bhabani Sankar Sahoo; Nils Fritjof Langlotz; Shachi Machchhar; Kartik Gaur; Robin Günkel; Max Bergmann; Naghmeh Ghadghooni; Aris Koulas-Simos; Jürgen Belz; Chirag Chandrakant Palekar; Maximilian Ries; Kerstin Volz; Stephan Reitzenstein; Imad Limame

arXiv · 2605.23418

Localized Excitonic Emission in Wafer-Scale MOCVD-Grown GaSe 2D Nanosheets for Classical and Non-Classical Light Sources

Bhabani Sankar Sahoo·Nils Fritjof Langlotz·Shachi Machchhar·Kartik Gaur·Robin Günkel·Max Bergmann·Naghmeh Ghadghooni·Aris Koulas-Simos·Jürgen Belz·Chirag Chandrakant Palekar·Maximilian Ries·Kerstin Volz·Stephan Reitzenstein·Imad Limame

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Abstract

Wafer-scale growth of two-dimensional semiconductors remains a key challenge for their integration into photonic technologies. While most studies of two-dimensional semiconductors have focused on transition metal dichalcogenides and their scalable fabrication, comparatively little attention has been given to III-VI monochalcogenides. Here, we report wafer-scale growth of gallium selenide (GaSe) by metal-organic chemical vapor deposition (MOCVD) and investigate its structural and optical properties for visible-range classical and quantum light emission. Two samples with thicknesses ranging from a few monolayers to several micrometers, controlled via the growth time, were investigated. The 30-minute grown sample yields intense, broad photoluminescence spanning 1.7--2.0$\,$eV, whereas the thinner 3-minute sample exhibits discrete narrow emission lines and single-photon emission with $(g^{(2)}(0) = 0.15 \pm 0.10)$. Remarkably, cathodoluminescence mapping reveals pronounced spatial localization of both spectrally narrow and broad emission centers. Together with temperature-dependent power-law analysis and Raman mapping, our results indicate defect-induced emission rather than intrinsic excitonic recombination. These findings establish wafer-scale MOCVD grown 2D GaSe as a platform for classical and non-classical light sources and highlight defect-engineered localization as a route toward scalable quantum photonics.

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Bhabani Sankar Sahoo, Nils Fritjof Langlotz, Shachi Machchhar, Kartik Gaur, Robin Günkel, Max Bergmann, Naghmeh Ghadghooni, Aris Koulas-Simos, Jürgen Belz, Chirag Chandrakant Palekar, Maximilian Ries, Kerstin Volz, Stephan Reitzenstein, Imad Limame. 2026-05-22. Localized Excitonic Emission in Wafer-Scale MOCVD-Grown GaSe 2D Nanosheets for Classical and Non-Classical Light Sources. https://arxiv.org/abs/2605.23418

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