Facet‐Driven Vapor Phase Growth of Directional Tin‐Doped CdS Nanowires on Sapphire Surface for Photodetectors

Abstract

Orientation‐controlled large‐area synthesis of nanowires (NWs) is key to their direct integration into circuits and devices for functional exploitation. Herein, the vapor–liquid–solid process yields planar arrays of tin‐doped CdS NWs with precise crystallographic orientation on flat and faceted sapphire surfaces. The nanopatterned catalyst and epitaxial correlation of each surface determine NWs’ exact position, yield, and orientation, while the graphoepitaxial effect steers their growth along the nanochannels. The incorporation of dopants widens the emission spectrum beyond the bandgap, which facilitates enhanced optical transport in NWs. Electron‐beam lithography (EBL) is employed to fabricate photodetector on individual NW, which demonstrates high photoresponsivity and fast response. Graphoepitaxial effect‐based assembly of highly ordered horizontal NW arrays and their facile self‐integration into devices for modern applications, including LEDs, biomedical or photoelectric sensors, photovoltaic cells, and visible span integrated optoelectronic and photonic systems, have promising prospects.