Academic Journal
Indirect to direct band gap crossover in two-dimensional WS2(1−x)Se2x alloys
| العنوان: | Indirect to direct band gap crossover in two-dimensional WS2(1−x)Se2x alloys |
|---|---|
| المؤلفون: | Ernandes C, Khalil L, Almabrouk H, Pierucci D, Zheng B, Avila J, Dudin P, Chaste J, Oehler F, Pala M, Bisti F, Brulé T, Lhuillier E, Pan A, Ouerghi A |
| المساهمون: | Ernandes, C, Khalil, L, Almabrouk, H, Pierucci, D, Zheng, B, Avila, J, Dudin, P, Chaste, J, Oehler, F, Pala, M, Bisti, F, Brulé, T, Lhuillier, E, Pan, A, Ouerghi, A |
| سنة النشر: | 2021 |
| المجموعة: | Università degli Studi di Udine: CINECA IRIS |
| الوصف: | In atomically thin transition metal dichalcogenide semiconductors, there is a crossover from indirect to direct band gap as the thickness drops to one monolayer, which comes with a fast increase of the photoluminescence signal. Here, we show that for different alloy compositions of WS 2(1− x ) Se 2 x this trend may be significantly affected by the alloy content and we demonstrate that the sample with the highest Se ratio presents a strongly reduced effect. The highest micro-PL intensity is found for bilayer WS 2(1− x ) Se 2 x ( x = 0.8) with a decrease of its maximum value by only a factor of 2 when passing from mono-layer to bi-layer. To better understand this factor and explore the layer-dependent band structure evolution of WS 2(1− x ) Se 2 x , we performed a nano-angle-resolved photoemission spectroscopy study coupled with first-principles calculations. We find that the high micro-PL value for bilayer WS 2(1− x ) Se 2 x ( x = 0.8) is due to the overlay of direct and indirect optical transitions. This peculiar high PL intensity in WS 2(1− x ) Se 2 x opens the way for spectrally tunable light-emitting devices. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| Relation: | info:eu-repo/semantics/altIdentifier/wos/WOS:000607934900001; volume:5; issue:1; journal:NPJ 2D MATERIALS AND APPLICATIONS; https://hdl.handle.net/11390/1266779; info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85098718708; http://www.nature.com/articles/s41699-020-00187-9 |
| DOI: | 10.1038/s41699-020-00187-9 |
| الاتاحة: | https://hdl.handle.net/11390/1266779 https://doi.org/10.1038/s41699-020-00187-9 http://www.nature.com/articles/s41699-020-00187-9 |
| رقم الانضمام: | edsbas.6749E2B9 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1038/s41699-020-00187-9 |
|---|