High-performance MoS2/Si heterojunction broadband photodetectors from deep ultraviolet to near infrared.

Polycrystalline 2D layered molybdenum disulfide (MoS2) films were synthesized via a thermal decomposition method. The MoS2/Si heterostructures were constructed in situ by synthesis MoS2 on plane Si substrates. Such MoS2/Si heterostructures exhibited high sensitivity to light illumination with wavelengths ranging from the deep ultraviolet to the near infrared. Photoresponse analysis reveals that a high responsivity of 23.1 A/W, a specific detectivity of 1.63×1012 Jones, and a fast response speed of 21.6/65.5 μs were achieved. Notably, the MoS2/Si heterojunction photodetector could operate with excellent stability and repeatability over a wide frequency range up to 150 kHz. The high performance could be attributed to the high-quality heterojunction between MoS2 and Si obtained by the in situ fabrication process. Such high performance with broadband response suggests that MoS2/Si heterostructures could have great potential in optoelectronic applications.