US EPA

4834796 

Journal Article 

Controlled Layer-by-Layer Etching of MoS₂ 

Lin, T; Kang, B; Jeon, M; Huffman, C; Jeon, J; Lee, S; Han, W; Lee, J; Lee, S; Yeom, G; Kim, K 

2015 

1 

ACS Applied Materials & Interfaces
ISSN: 1944-8244
EISSN: 1944-8252 

7 

29 

15892-15897 

English 

26091282 

10.1021/acsami.5b03491 

WOS:000358897200024 

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.