Wet-Transferred MoS₂ on Passivated InP: A Van der Waals Heterostructure for Advanced Optoelectronic Applications

III–V semiconductors are considered ideal materials for optoelectronic applications due to their direct bandgap and wide tunable range of bandgap energy. However, optoelectronic devices based on III–V have been plagued by significant surface recombination due to imperfect surface bonding. Meanwhile, 2D transition metal dichalcogenides (TMDs) exhibit unique electrical properties, including a dangling bond-free surface, which has led to extensive research into their potential for electronic applications. However, optical devices such as photodetectors utilizing 2D-TMDs have received relatively little attention, primarily because they are inefficient at absorbing photons independently. In this study, a photodetector employing atomically thin layers of MoS₂ on InP substrate is demonstrated. The n-MoS₂/p-InP device exhibits excellent rectifying properties with an ideality factor of 1.57, indicating the formation of a type-II staggered heterojunction. The photoresponsivity of the heterojunction device is measured across a wavelength range of 300–1000 nm, with a maximum value of 960 mA W⁻¹. Notably, the MoS₂ layers provide a stable passivation effect on the imperfect InP crystal surface.