Enhanced rectification, transport property and photocurrent generation of multilayer ReSe₂/MoS₂ p–n heterojunctions

Van der Waals (vdW) heterojunctions are equipped to avert dangling bonds due to weak, inter-layer vdW force, and ensure strong in-plane covalent bonding for two-dimensional layered structures. We fabricated four heterojunctions devices of different layers based on p-type distorted 1T-MX₂ ReSe₂ and n-type hexagonal MoS₂ nanoflakes, and measured their electronic and optoelectronic properties. The device showed a high rectification coefficient of 500 for the diode, a high ON/OFF ratio and higher electron mobility for the field-effect transistor (FET) compared with the individual components, and a high current responsivity (R_λ) and external quantum efficiency (EQE) of 6.75 A/W and 1, 266%, respectively, for the photodetector.