Quantum Coherent Coupling in Adjacent Silicon Nanowires Yields Non-Ohmic Photocurrent Enhancement.

Nanostructured photovoltaic and optoelectronic devices are of broad importance due to their outstanding potential in applications from photodetectors to solar cells. In densely packed nanoscale systems, device performance arises not only from individual nanowires but also from complex, coherent internanowire interactions. Here, we employ large-scale (∼11,500 atom) quantum transport simulations using density functional tight-binding and nonequilibrium Green's function (DFTB+NEGF) formalisms, including electron-photon interactions, to investigate how adjacent doped silicon nanowire photovoltaic devices, each incorporating a p-n junction and operating as an active optoelectronic component, collectively respond to illumination. The simulations reveal a novel photocurrent enhancement driven by coherent coupling between neighboring nanowires. This coupling creates new interfacial electronic states and yields a non-Ohmic photocurrent response, with the effect strongly dependent on nanowire spacing. These findings indicate that engineering interwire spacing, and interfaces can create beneficial quantum states that improve efficiency, guiding a new design strategy for high-performance nanoscale photovoltaic devices.