In situ tailoring of two-dimensional materials’ phases under external stimulus facilitates the manipulation of their properties for electronic, quantum and energy applications. However, current methods are mainly limited to the transitions among phases with unchanged chemical stoichiometry. Here we propose on-device phase engineering that allows us to realize various lattice phases with distinct chemical stoichiometries. Using palladium and selenide as a model system, we show that a PdSe₂ channel with prepatterned Pd electrodes can be transformed into Pd₁₇Se₁₅ and Pd₄Se by thermally tailoring the chemical composition ratio of the channel. Different phase configurations can be obtained by precisely controlling the thickness and spacing of the electrodes. The device can be thus engineered to implement versatile functions in situ, such as exhibiting superconducting behaviour and achieving ultralow-contact resistance, as well as customizing the synthesis of electrocatalysts. The proposed on-device phase engineering approach exhibits a universal mechanism and can be expanded to 29 element combinations between a metal and chalcogen. Our work highlights on-device phase engineering as a promising research approach through which to exploit fundamental properties as well as their applications.

在外部刺激下对二维材料的相进行原位定制有助于控制其在电子、量子和能源应用中的特性。然而，目前的方法主要限于化学计量不变的相之间的转变。在这里，我们提出了器件上的相工程，使我们能够实现具有不同化学计量的各种晶格相。使用钯和硒化物作为模型系统，我们表明具有预图案化Pd电极的PdSe ₂通道可以通过热调整通道的化学成分比而转化为Pd ₁₇ Se ₁₅和Pd ₄ Se。通过精确控制电极的厚度和间距可以获得不同的相配置。因此，该设备可以被设计为在原位实现多种功能，例如表现出超导行为和实现超低接触电阻，以及定制电催化剂的合成。所提出的器件上相工程方法展示了一种通用机制，并且可以扩展到金属和硫族元素之间的 29 种元素组合。我们的工作强调了设备上的相位工程作为一种有前途的研究方法，通过它来开发基本特性及其应用。