Voltage-assisted selective growth of ZnO nanowires on metal/semiconductor surfaces employing hydrothermal double-step CBD/CBD growth technique

The current work demonstrates a voltage-assisted double-step Chemical Bath Deposition (CBD/CBD) growth technique for the simultaneous selective growth of ZnO nanowires (NWs) on conducting Nickel Silicide (NiSi) and semiconducting surfaces (p-Si substrate). An applied potential difference across the NiSi strip, during such CBD growth, enabled the growth of dense, uniform and well-aligned ZnO NWs with varying stoichiometric compositions along the strip. The surface morphology, absorption characteristics, chemical stoichiometric compositions, and crystalline properties of such voltage-assisted grown nanowires are studied by employing field emission scanning electron microscopy (FESEM), UV-Visible absorption, and energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), respectively. Such studies confirmed the selective growth of ZnO NWs with varying diameter, alignment, growth density and ratio of at%, corroborating the observed variation of electric field lines obtained from the relevant simulations. The applied bias reduces surface barrier to enable the growth of ZnO NWs on NiSi strip. Photoluminescence measurements confirmed the significant reduction of deep-level emission peak which appears due to oxygen-related defect states at 628 nm in such voltage-assisted grown ZnO NWs. Thus, the proposed voltage-assisted selective growth method provides an additional control over the conventional CBD technique for large-scale production of the dense and well-aligned ZnO NWs on NiSi surfaces with less defect states.