Vapor Phase Selective Growth of Two-Dimensional Perovskite/WS2 Heterostructures for Optoelectronic Applications

Organic-inorganic hybrid perovskites have attracted increased interest owing to their exceptional optoelectronic properties and promising applications. Monolayers of transition metal dichalcogenides (TMDCs), such as tungsten disulfide (WS2), are also intriguing because of their unique optoelectronic properties and their atomically thin and flexible structures. Therefore, the combination of these different types of materials is very attractive in terms of fundamental science of interface interaction, as well as for the realization of ultrathin optoelectronic devices with high performance. Here, we demonstrate the controlled synthesis of two-dimensional (2D) perovskite/WS2 heterostructures by an all vapor-phase growth approach. This involves the chemical vapor deposition (CVD) growth of monolayer WS, followed by the vapor-phase selective deposition of 2D PbI2, onto the WS2 with the successive conversion of PbI2, to organic-inorganic perovskite (CH3NH3PbI3). Moreover, the selective growth of the perovskite on prepatterned WS2 enables the direct synthesis of patterned heterostructures, avoiding any damage to the perovskite. The photodetectors utilizing the perovskite/WS2 heterostructure show increased responsivities compared with isolated thin perovskite obtained by conventional solution methods. The integration of 2D perovskite with TMDCs opens a new avenue to fabricate advanced devices by combining their unique properties and overcoming current processing difficulties of perovskites.

有机 - 无机杂化钙钛矿由于其优异的光电性能和良好的应用前景而受到越来越多的关注。过渡金属二硫化物（TMDCs）的单层材料，如二硫化钨（WS₂），因其独特的光电性能以及原子级薄且灵活的结构也很吸引人。因此，这些不同类型材料的组合在界面相互作用的基础科学方面以及实现高性能超薄光电器件方面都极具吸引力。在此，我们展示了通过全气相生长方法对二维（2D）钙钛矿/WS₂异质结构的可控合成。这包括化学气相沉积（CVD）生长单层WS₂，然后在WS₂上气相选择性沉积二维PbI₂，并将PbI₂依次转化为有机 - 无机钙钛矿（CH₃NH₃PbI₃）。此外，在预先图案化的WS₂上选择性生长钙钛矿能够直接合成图案化的异质结构，避免对钙钛矿造成任何损伤。与通过常规溶液方法获得的孤立薄钙钛矿相比，利用钙钛矿/WS₂异质结构的光电探测器显示出更高的响应度。二维钙钛矿与过渡金属二硫化物的集成通过结合它们的独特性能并克服钙钛矿当前的加工困难，为制造先进器件开辟了一条新途径。