Growth of Si2Te3/Si heterostructured nanowire and its photoresponse property

Single-crystalline heterostructured Si2Te3/Si nanowires (H-NWs) were synthesized by using gold nanoclusters as a catalyst. Control of the nanowire structures could be achieved by substrate temperature and growth time. Scanning electron microscopy (SEM) study shows that the as-grown nanowires are composed of two parts: one part has a conical shape with gold catalyst on the top and second part is uniform nanowire. High-resolution transmission microscopy study shows that the H-NWs have a core/shell structure with a silicon nanowire core wrapped by a Si2Te3 shell. The composition of the core-shell structure was confirmed by Energy-dispersive X-ray spectrometry (EDX) measurements. X-ray diffraction (XRD) and Raman spectra confirm the two types of crystal structure of silicon and Si2Te3 in H-NWs. A possible growth mechanism of H-NWs is discussed. The photoresponse property of Si2Te3/Si H-NW is observed under illumination of light. The rise and decay time constants are τr∼590 ms and τd∼800 ms, respectively. The unique structure and properties of these silicon-based nanowires of 2D materials are not only interesting for fundamental understanding but also potential building blocks for applications in optoelectronic devices.