High-performance photodetector based on MoS2/vertical graphene.

Graphene offers a broad spectral response as a photodetector sensing layer with its zero-bandgap structure. However, its atomic thickness restricts light absorption to merely about 2% in the visible spectrum. To address this, MoS₂has been integrated with graphene to form heterojunctions, thereby enhancing light absorption and facilitating efficient electron-hole pair separation. Nevertheless, this approach involves complex transfer processes and still leaves room for improving light absorption efficiency. This study presents the fabrication of a high-performance photodetector based on a MoS₂/vertical graphene (VG) composite. VG, prepared via plasma-enhanced chemical vapor deposition (CVD), provides an ultra-high absorption rate of 97% across the 400-2000 nm wavelength range. Few-layer MoS₂is directly grown on VG using CVD process, thereby eliminating the transfer process. The resulting MoS₂/VG based photodetector inherits VG's superior light absorption, exhibiting significantly enhanced photocurrent responses, with a responsivity of 10.4 mA W^-1and rise/decay times lower than 300 ms. The detector exemplifies the synergistic enhancement between MoS₂and VG, highlighting its significant potential for future broadband optoelectronic applications.