Engineering Light Outcoupling in 2D Materials

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• 作者：Der-Hsien Lien ; Jeong Seuk Kang ; Matin Amani ; Kevin Chen ; Mahmut Tosun ; Hsin-Ping Wang ; Tania Roy ; Michael S. Eggleston ; Ming C. Wu ; Madan Dubey ; Si-Chen Lee ; Jr-Hau He ; Ali Javey
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：February 11, 2015
• 年：2015
• 卷：15
• 期：2
• 页码：1356-1361
• 全文大小：418K
• ISSN：1530-6992

文摘

When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe₂, resulting in a 鈭?1 times increase in Raman signal and a 鈭?0 times increase in the photoluminescence (PL) intensity of WSe₂. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe₂. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.