Dynamic modulations of photocurrent (PC) have recently attracted great attention owing to their promising photo-involved energy applications in fields such as optoelectronics and photonics, which relies on the charge transition through optical absorption (OA). Typically, the magnetic-field-controlled optical phenomena in nano-heterostructures consisting of magnetic-components can be determined by density of states (DOSs), it is important to elucidate interrelations between the band structure and the magnetic response.

A promising alternative to engineering of spin-polarized DOSs relies on the interfacial charge transfer between charge reservoirs and suppliers in many vacancy-rich non-magnetic nanostructures with a high unoccupied DOSs. Engineering spin-polarized band introduces directly magnetic field to dynamic control the optical absorption (MOA) and associated photocurrent (MPC), which allows photosensitive semiconductor material to greatly enhance the range of applicability, however it rarely explored.

In this study, the alternately sizeable negative and positive MOA and MPC effects can be tuned in a-C/ZnO NWs by controlling the sp²/sp³ ratio of a-C through the charge-transfer-induced spin-polarized band. The substantial MPC enhancement (~15 %) was observed when using a relatively low magnetic field ~ 0.2 T at room temperature. Simulated two peaks of the spin-polarized density of states can be used to reasonably explain that the sequences of transformation of MOA is mainly contributed by the manipulation of charge transfer between ZnO and C. This study can motivate the further exploration of MOA and MPC effects in photo-sensitive semiconductor materials, which can enable achieving magnetic field enhanced performance in energy-related fields and tunable photonic applications to be met. The effectiveness of MOA and MPC depends on the spin polarization properties of the two nano-heterostructures and it may vary from materials to materials.We believe the results presented herein provide new domains of magnetic-field-controlled and photo-involved energy applications issues.