Thickness-Dependent Dielectric Constant of Few-Layer In2Se3 Nanoflakes

详细信息    查看全文

• 作者：Di Wu ; Alexander J. Pak ; Yingnan Liu ; Yu Zhou ; Xiaoyu Wu ; Yihan Zhu ; Min Lin ; Yu Han ; Yuan Ren ; Hailin Peng ; Yu-Hao Tsai ; Gyeong S. Hwang ; Keji Lai
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：8136-8140
• 全文大小：350K
• ISSN：1530-6992

文摘

The dielectric constant or relative permittivity (蔚_r) of a dielectric material, which describes how the net electric field in the medium is reduced with respect to the external field, is a parameter of critical importance for charging and screening in electronic devices. Such a fundamental material property is intimately related to not only the polarizability of individual atoms but also the specific atomic arrangement in the crystal lattice. In this Letter, we present both experimental and theoretical investigations on the dielectric constant of few-layer In₂Se₃ nanoflakes grown on mica substrates by van der Waals epitaxy. A nondestructive microwave impedance microscope is employed to simultaneously quantify the number of layers and local electrical properties. The measured 蔚_r increases monotonically as a function of the thickness and saturates to the bulk value at around 6鈥? quintuple layers. The same trend of layer-dependent dielectric constant is also revealed by first-principles calculations. Our results of the dielectric response, being ubiquitously applicable to layered 2D semiconductors, are expected to be significant for this vibrant research field.