(Invited) Layer Control of 2D-MoS2 by Atomic Layer Etching and Its Device Characteristics

Abstract

Molybdenum disulfide (MoS2) has been intensively investigated due to its unique properties in various electronic and optoelectronic applications with different band-gap energies from 1.29 to 1.9 eV as the number of layers is decreased. To control the MoS2 layers, atomic layer etching (ALE) composed of a Cl radical adsorption step and a reacted-compound desorption step via a low-energy Ar+-ion exposure can be a highly effective technique to avoid damage and contamination that occur during the cyclic steps. In this presentation, MoS2 ALE is compared with conventional plasma etching, and the MoS2-ALE mechanism is reported with the results of an experiment and a simulation. Especially, using the ALE method, mono-layer/bi-layer MoS2 field effect transistors (FETs) were fabricated and their electrical characteristics were investigated and compared with the MoS2 FETs fabricated with pristine mono-layer/bi-layer MoS2. In addition, mono-/multi-layer lateral-heterojunction device was fabricated using the ALE technique after photoresist patterning of multi-layer MoS2.