Red-to-Ultraviolet Emission Tuning of Two-Dimensional Gallium Sulfide/Selenide

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• 作者：Chan Su Jung ; Fazel Shojaei ; Kidong Park ; Jin Young Oh ; Hyung Soon Im ; Dong Myung Jang ; Jeunghee Park ; Hong Seok Kang
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：9
• 期：10
• 页码：9585-9593
• 全文大小：746K
• ISSN：1936-086X

文摘

Graphene-like two-dimensional (2D) nanostructures have attracted significant attention because of their unique quantum confinement effect at the 2D limit. Multilayer nanosheets of GaS鈥揋aSe alloy are found to have a band gap (E_g) of 2.0鈥?.5 eV that linearly tunes the emission in red-to-green. However, the epitaxial growth of monolayers produces a drastic increase in this E_g to 3.3鈥?.4 eV, which blue-shifts the emission to the UV region. First-principles calculations predict that the E_g of these GaS and GaSe monolayers should be 3.325 and 3.001 eV, respectively. As the number of layers is increased to three, both the direct/indirect E_g decrease significantly; the indirect E_g approaches that of the multilayers. Oxygen adsorption can cause the direct/indirect E_g of GaS to converge, resulting in monolayers with a strong emission. This wide E_g tuning over the visible-to-UV range could provide an insight for the realization of full-colored flexible and transparent light emitters and displays.