Controlled Layer-by-Layer Etching of MoS2

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• 作者：TaiZhe Lin ; BaoTao Kang ; MinHwan Jeon ; Craig Huffman ; JeaHoo Jeon ; SungJoo Lee ; Wei Han ; JinYong Lee ; SeHan Lee ; GeunYoung Yeom ; KyongNam Kim
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：July 29, 2015
• 年：2015
• 卷：7
• 期：29
• 页码：15892-15897
• 全文大小：442K
• ISSN：1944-8252

文摘

Two-dimensional (2D) metal dichalcogenides like molybdenum disulfide (MoS₂) may provide a pathway to high-mobility channel materials that are needed for beyond-complementary metal-oxide-semiconductor (CMOS) devices. Controlling the thickness of these materials at the atomic level will be a key factor in the future development of MoS₂ devices. In this study, we propose a layer-by-layer removal of MoS₂ using the atomic layer etching (ALET) that is composed of the cyclic processing of chlorine (Cl)-radical adsorption and argon (Ar)⁺ ion-beam desorption. MoS₂ etching was not observed with only the Cl-radical adsorption or low-energy (<20 eV) Ar⁺ ion-beam desorption steps; however, the use of sequential etching that is composed of the Cl-radical adsorption step and a subsequent Ar⁺ ion-beam desorption step resulted in the complete etching of one monolayer of MoS₂. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) indicated the removal of one monolayer of MoS₂ with each ALET cycle; therefore, the number of MoS₂ layers could be precisely controlled by using this cyclical etch method. In addition, no noticeable damage or etch residue was observed on the exposed MoS₂.