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 WS₂, 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.