Direct integration of polycrystalline graphene on silicon as a photodetector via plasma-assisted chemical vapor deposition

Abstract

Graphene that is directly integratable into electronic devices after its growth is highly desirable but is difficult to fabricate due to its relatively high growth temperatures (∼1000 °C) and inevitable transfer step. Herein, we propose a convenient and feasible strategy to directly synthesize high-quality polycrystalline graphene on Si substrates by utilizing plasma-assisted chemical vapor deposition (PACVD), where three main features inevitable to traditional growth methods, i.e., transition metals as catalysts, post-transfer process and high growth temperature, can be thoroughly circumvented. Notably, the growth temperature is significantly reduced and reaches as low as 700 °C. The utilized PACVD provides exceptional abilities of hydrocarbon pyrolysis and graphene formation even on unusual Si substrates. Furthermore, the as-grown graphene-on-Si (GOS) exhibits superior capabilities that can be used to directly fabricate high performance optoelectronic devices, e.g., photodetectors. Typical current rectification characteristics and good photovoltaic conversion efficiency are demonstrated in as-grown graphene/Si Schottky junctions.