Presentation Information
[20a-A202-4]Development of atomic layer etching method for WTe2 single crystals
〇Manabu Ohtomo1, Naoki Fushimi1, Masayuki Hosoda1,2, Junichi Yamaguchi1, Russell Deacon2, Michael Randle2, Kenichi Kawaguchi1, Koji Ishibashi2, Shintaro Sato1 (1.Fujitsu Ltd., 2.RIKEN)
Keywords:
topological insulator,Tungsten ditelluride,Atomic layer etching
The monolayer 1T’ phase of tungsten ditelluride (WTe2) exhibits properties as a two-dimensional topological insulator, which makes it a promising platform for topological qubits in the fault-tolerant quantum computation. In this study, we report on the atomic layer etching (ALE) method of WTe2 for efficient electrode junction formation in Josephson junction devices of monolayer WTe2. ALE method developed in this study is based on the self-limiting surface oxidation and oxide removal by KOH treatment. After optimization of the surface oxidation method in WTe2, it was found that ozone oxidation by direct irradiation of UV light was too strong for WTe2 and did not result in self-limiting oxidation, while self-limiting moderate oxidization was achieved by shielding UV light. The etching rate for each ALE cycle was estimated to be approximately 0.7 -1.2 nm/cycle, which corresponds well with the monolayer thickness of WTe2 (0.7 nm thick).