Optical properties of Bi2Se3: from bulk to ultrathin films

被引：46

作者：

Eddrief, M. ^{[1
]}

Vidal, F. ^{[1
]}

Gallas, B. ^{[1
]}

机构：

[1] UPMC Univ Paris 06, Sorbonne Univ, CNRS UMR 7588, Inst NanoSci Paris, F-75005 Paris, France

来源：

JOURNAL OF PHYSICS D-APPLIED PHYSICS | 2016年 / 49卷 / 50期

关键词：

topological insulator; optical constants; thin films; ELECTRONIC-STRUCTURE; SURFACE;

D O I：

10.1088/0022-3727/49/50/505304

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

We report on the determination of the dielectric functions of Bi2Se3 thin films and bulk material. The Bi2Se3 thin films with thicknesses ranging from 3-54 quintuple layers (QL) were grown by molecular beam epitaxy on GaAs(1 1 1) B substrates and the optical properties were determined from spectroscopic ellipsometry in the range of 0.5 eV-6eV. We observed five absorption bands in the bulk sample, with a strong maximum near 2 eV, which were also present in the films down to 19 QL. Reducing the number below 19 QL in the Bi2Se3 films caused dampening and broadening of the bulk absorption bands below 2 eV, and a shift to a higher energy of the band near 2 eV. Our experimental results thus provide evidence of marked changes in the joint density of states of Bi2Se3 below 19 QL, indicating that the whole bulk band structure is affected for the ultrathin epilayers.

引用

页数：9

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