Nanoarchitectonics for granular systems: in the case of disordered Mo–SiO x thin films

Abstract

Granular systems composed of metallic granules embedded as artificial atoms in the insulating matrix, have been extensively studied over the last decade due to their importance for nanotechnological applications and fundamental research on disordered materials. However, fabrication of uniform granular systems with tunable functionalities is still challenging. Here, from a nanoarchitectonic perspective, we proposed a general fabrication approach which exploits the different oxygen affinity between involving chemical elements to realize granular systems. Such a routine was demonstrated in the prototypical Mo–SiO x granular systems when the Mo–Si alloy target was sputtered at room temperature under oxygen-poor conditions. This growth approach produces highly disordered Mo–SiO x granular thin films, which exhibit the tunable electronic behavior, and huge photo-response (I L/I D up to 107 at 100 K), over 100% external quantum efficiency (in the wavelength range of 500–750 nm) and a short response time (∼3 ms). Our work provides a new design principle for fabricating granular systems with tunable functionalities, which lays the foundation for understanding novel physical phenomena and rational design of multi-functional devices.