Strain lithography for two-dimensional materials by electron irradiation

Abstract

Strain engineering, aiming to tune physical properties of semiconductors, provides a promising paradigm for modern micro/nanoelectronics. Two-dimensional materials (2DMs) are the ideal candidates for the next generation of strain engineered devices because of their intrinsic exceptional mechanical flexibility and strength. However, conventional strain modulation methods in 2DMs cannot satisfy the demand of future device applications, because strained structures by these methods lack consistency, reproducibility, and design flexibility. Here, based on the photoresist degeneration induced by electron irradiation, we present a non-contact approach to accurately and directly write the strains with designed patterns from the nanometer to micrometer scale in 2DMs. Profit from controllable manipulation of the electron beam, the developed strategy offers a capability for constructing tensile, compress, or complex strains in MoSe2 monolayers; hence, unique electronic structures for unique physical properties can be designed. Aside from 2DMs, this approach is also appropriate for other types of materials such as Au, α-Si, and Al2O3. Its flexibility and IC-compatibility allow our strain lithography methodology promising in accelerating the potential applications of 2DMs in extensive fields ranging from nanoelectromechanical systems, high-performance sensing, and nontraditional photovoltaics to quantum information science.