Capillary-Force-Driven Switchable Delamination Of Nanofilms And Its Application To Green Selective Transfer

Technology for transferring nanofilm patterns is important in the fabrication of next-generation electronic devices. However, with existing transfer methods, selective control of the delamination region is challenging without recourse to conventional lithographic techniques, which involve equipment-intensive and toxic-chemical etching processes. Here, capillary-force-driven switchable delamination of nanofilms and its application to a green selective transfer process are presented. The capillary-force-driven delamination is easily and spontaneously implemented by dipping an Au-Si specimen into water at an oblique angle; no other chemicals or additional processes are required. Moreover, the delamination behavior is switched by changing the hydrophobic Au surface to hydrophilic. The mechanism of switchable delamination is investigated by considering the primary influencing factors which are wettability of Au surface and surface tension of water platform. The switchable delamination allows the selective transfer of nanofilm patterns by locally modulating surface wettability. Diverse nanofilm patterns and structures including spiral, serpentine, and van der Waals heterostructures are demonstrated. Furthermore, various nanofilm materials are used in the transfer process by exploiting Au nanofilm as a debonding layer. Finally, a unique technique for assembly and one-step transfer of nanofilm devices is suggested using the selective transfer method.