Interface Engineering of a Silicon/Graphene Heterojunction Photodetector via a Diamond-Like Carbon Interlayer

Silicon/graphene nanowalls (Si/GNWs) heterojunctions with excellent integrability and sensitivity show an increasing potential in optoelectronic devices. However, the performance is greatly limited by inferior interfacial adhesion and week electronic transport caused by the horizontal buffer layer. Herein, a diamond-like carbon (DLC) interlayer is first introduced to construct Si/DLC/GNWs heterojunctions, which can significantly change the growth behavior of the GNWs film, avoiding the formation of horizontal buffer layers. Accordingly, a robust diamond-like covalent bond with a remarkable enhancement of the interfacial adhesion is yielded, which notably improves the complementary metal oxide semiconductor compatibility for photodetector fabrication. Importantly, the DLC interlayer is verified to undergo a graphitization transition during the high-temperature growth process, which is beneficial to pave a vertical conductive path and facilitate the transport of photogenerated carriers in the visible and near-infrared regions. As a result, the Si/DLC/GNWs heterojunction detectors can simultaneously exhibit improved photoresponsivity and response speed, compared with the counterparts without DLC interlayers. The introduction of the DLC interlayer might provide a universal strategy to construct hybrid interfaces with high performance in next-generation optoelectronic devices.