Rapid laser nanomanufacturing and direct patterning of 2D materials on flexible substrates - 2DFlex.

Direct synthesis, large-scale integration, and patterning of two-dimensional (2D) quantum materials (e.g., MoS\u003csub\u003e2\u003c/sub\u003e, WSe\u003csub\u003e2\u003c/sub\u003e) on flexible and transparent substrates are of high interest for the flexible and conformal device applications. However, the growth temperature (e.g., 850 °C) of the emerging 2D materials in the common gas-phase synthesis methods are well beyond the tolerances limit of flexible substrates, such as polydimethylsiloxane (PDMS). In addition, random nucleation and growth process in most growth systems limits the predicted integration and patterning freedoms. Here, we report a rapid direct laser crystallization and mask-free large-scale patterning of MoS\u003csub\u003e2\u003c/sub\u003eand WSe\u003csub\u003e2\u003c/sub\u003ecrystals on PDMS substrates. A thin layer of stoichiometric amorphous 2D film is first laser deposited via pulsed laser deposition (PLD) system onto the flexible substrates followed by a controlled crystallization and direct writing process using a tunable nanosecond laser (1064 nm). The influences of pulse duration, number of pulses, and the thickness of the deposited amorphous 2D layer on the crystallization of 2D materials are discussed. Optical spectroscopy and electrical characterizations are performed to confirm the quality of crystallized 2D materials on flexible substrates. This novel method opens up a new opportunity for the crystallization of complex patterns directly from computer-aided design models for the future 2D materials-based wearable, transparent, and flexible devices.