  Owing to its outstanding electronic properties, black phosphorus (BP) is
considered as a promising material for next-generation optoelectronic devices.
In this work, devices based on BP/MXene (Zrn+1CnT2, T = O, F, OH, n = 1, 2) van
der Waals (vdW) heterostructures are designed via first-principles
calculations. Zrn+1CnT2 compositions with appropriate work functions lead to
the formation of Ohmic contact with BP in the vertical direction. Low Schottky
barriers are found along the lateral direction in BP/Zr2CF2, BP/Zr2CO2H2,
BP/Zr3C2F2, and BP/Zr3C2O2H2 bilayers, and BP/Zr3C2O2 even exhibits Ohmic
contact behavior. BP/Zr2CO2 is a semiconducting heterostructure with type-II
band alignment, which facilitates the separation of electron-hole pairs. The
band structure of BP/Zr2CO2 can be effectively tuned via a perpendicular
electric field, and BP is predicted to undergo a transition from donor to
acceptor at a 0.4 V/{\AA} electric field. The versatile electronic properties
of the BP/MXene heterostructures examined in this work highlight their
promising potential for applications in electronics.
