IMPROVING GROWTH OF ZnO NANOSTRUCTURES ON D-SHAPE FIBER BY MOLARITY CONTROL

Abstract

ZnO nanostructures are promising for photonic applications, but achieving uniform growth on D-shaped optical fibres remains challenging due to precursor molarity effects. This study optimizes hydrothermal synthesis conditions (0.02–0.06 M) for ZnO growth on side-polished D-shaped fibres (~3 dB loss). Characterization (FESEM, EDX, ImageJ) shows that low molarity (0.02 M) produces sparse rod-like structures, while 0.03–0.04 M yields dense, vertically aligned nanorods (33–42 nm) with optimal morphology for evanescent sensing. Higher molarities (0.05–0.06 M) lead to coalesced films and irregular aggregates with compositional imbalances. The optimal range (0.03–0.04 M) offers the best structural quality, supporting applications in sensing and diagnostics.