BP/MoS₂ Van Der Waals Heterojunctions for Self‐Powered Photoconduction

2D materials can be combined without the need for lattice matching, leading to various van der Waals heterostructures with novel functionalities. Herein, it focuses on a vertical heterostructure made of thin black phosphorus (BP) over monolayer molybdenum disulfide (MoS2) that is characterized using a four-probe configuration. The device exhibits contact resistance negligible compared to the resistance of the BP/MoS2 channel, rectifying current-voltage (IV) characteristics, dominant n-type conduction resulting from type II band alignment and field effect mobility ≈1 cm2 V−1 s−1 limited by MoS2. An energy barrier at the BP/MoS2 interface of 68 meV is estimated using IV measurements at different temperatures. Additionally, the BP/MoS2 device exhibits fast photoresponse, conductance depending linearly on the incident light power, and photovoltaic effect, suggesting its suitability for self-powered photodetection. The spectral response is nearly constant in the 450 − 600 nm range and declines for wavelengths above 600 nm, that is for light energies below the energy bandgap of MoS2. Both the short circuit current Isc and the open circuit voltage Voc show a dependence on the incident power and wavelength, with maximum values Isc ≈ 0.12 nA and Voc ≈ 75 mV under 126 µW incident white light power. These findings highlight the potential of BP/MoS₂ heterojunctions for optoelectronic applications.