Self-selected growth of catalyst-free ZnO nanowires on 2D transition metal dichalcogenides

In this study, the selective, catalyst-free synthesis of ZnO nanowires (NWs) heterostructures on transition-metal dichalcogenides (TMDs) is demonstrated. First, triangular domains of MoS2 or WS2 were synthesized using an ambient two-stage chemical vapor deposition (CVD) method. Subsequently, dense ZnO NWs with preferential vertical orientation were produced through the selective nucleation and growth process exclusively on the TMD surfaces. Microscopic and spectroscopic analyses were performed to verify crystalline and chemical integrity of the heterostructure and the interfaces. Deterministic placement is achieved by pre-patterning the TMD catalyst precursors using the Direct-Write Patterning (DWP) approach, resulting in periodic ZnO NW-on-TMD micro-arrays. The broad bandgap and piezoelectric characteristics of ZnO NWs, together with the gate-tunable conductivity of TMDs, could enable efficient charge separation and field-effect/piezo-phototronic interactions. This versatile, mask-free method facilitates site-specific direct synthesis of 2D-1D heterostructures and their future integration into highly responsive devices and 3D platforms, such as photodetectors, quantum devices and circuits, piezo-phototronic and pressure/strain sensors, just to name a few.

.Progress towards specific device realization and testing will be reported.