Synthesis of Si Nanosheets by a Chemical Vapor Deposition Process and Their Blue Emissions

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• 作者：Ungkil Kim ; Ilsoo Kim ; Yonghee Park ; Ki-Young Lee ; Sang-Youp Yim ; Jae-Gwan Park ; Hong-Gyu Ahn ; Seung-Han Park ; Heon-Jin Choi
• 刊名：ACS Nano
• 出版年：2011
• 出版时间：March 22, 2011
• 年：2011
• 卷：5
• 期：3
• 页码：2176-2181
• 全文大小：840K
• 年卷期：0
• ISSN：1936-086X

文摘

We synthesized free-standing Si nanosheets (NSs) with a thickness of about <2 nm using a chemical vapor deposition process and studied their optical properties. The Si NSs were formed by the formation of frameworks first along six different ⟨110⟩ directions normal to [111], its zone axis, and then by filling the spaces between the frameworks along the ⟨112⟩ directions under high flow rate of processing gas. The Si NSs showed blue emission at 435 nm, and absorbance and photoluminescence (PL) excitation measurements indicate that enhanced direct band transition attributes to the emission. Time-resolved PL measurement, which showed PL emission at 435 nm and a radiative lifetime of 1.346 ns, also indicates the enhanced direct band gap transition in these Si NSs. These outcomes indicate that dimensionality of Si nanostructures may affect the band gap transition and, in turn, the optical properties.