Local Modulation of Electrical Transport in 2D Layered Materials Induced by Electron Beam Irradiation

Abstract

Effective doping techniques that precisely and locally control the conductivity and carrier polarity, i.e., electron (n-type) or hole (p-type), play a vital role in the remarkable success of Si-based technology and thus are critical for developing useful devices based on two-dimensional layered transition-metal dichalcogenides (TMDs). In contrast to the previous approaches based on either chemical doping or phase transition that requires complex chemicals or a high thermal budget and shows limited tunability and reliability, we propose a simple yet effective electron-beam irradiation (EBI) technique as an alternative for facilitating polarity transformation and transport modulation in selected regions. The EBI process may generate a precise amount of native chalcogen defects in both MoS2 and MoTe2 by controlling the EBI dosage. First-principles simulations support that the presence of native chalcogen vacancies may substantially reduce the band gaps of TMDs. In MoTe2, the progressive evolution of p-type c...