A supersensitive, ultrafast, and broadband light-harvesting scheme employing carbon nanotube/tio₂ core-shell nanowire geometry

We demonstrate a novel, feasible strategy on practical application of one-dimensional photodetectors by integrating carbon nanotube and TiO₂ in a core-shell fashion for breaking the compromise between the photogain and the response/recovery speed. Radial Schottky barriers between carbon nanotube cores and TiO₂ shells and surface states at TiO₂ shell surface regulate electron transport and also facilitate the separation of photo-generated electrons and holes, leading to ultrahigh photogain (G = 1.4×104) and the ultrashort response/recovery times (4.3/10.2 ms). Additionally, radial Schottky junction and defect band absorption broaden the detection range (UV-visible). The concept using metallic core-oxide shell geometry with radial Schottky barriers holds potential to paves a new way to realize nanostructured photodetectors in a practical use.