Synergistic Enhancement of Photodetector Performance Using Annealed Mushroom‑Shaped Indium Caps on GLAD‑Engineered TiO₂ Nanowires

Photodetectors based on metal–oxide nanostructures often struggle with slow response times and inefficient charge transport due to interfacial defects and limited carrier pathways. In this work, we combine glancing angle deposition (GLAD) with electron‑beam evaporation to grow TiO₂ nanowires and decorate them with annealed, mushroom‑shaped Indium caps. This simple morphological modification creates an enlarged metal–semiconductor contact area and strengthens the local electric field at the junction, improving carrier separation and transport. The unique Indium morphology was achieved by optimizing GLAD parameters, while n-type Si served as the substrate and Cu contacts served as the electrode. Structural and compositional characterizations were performed using field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD). The XRD results confirmed the formation of TiO₂ in the anatase phase along with Indium’s tetragonal phase structure. UV–Vis spectroscopy results exhibited absorption bands around 250 nm, 400–440 nm, and extending past 600 nm, confirming the broad optical response of the device. Electrical measurements revealed an ideality factor of 13.6, a high detectivity (D*) of 4.5810 ⁸ Jones, and a low noise equivalent power (NEP) of 2.90×10⁻ ¹⁰ W. Furthermore, transient photoresponse measurements demonstrated fast switching behavior with rise and decay times of 0.08 s and 0.08 s, respectively. These results suggest that morphological control of Indium through GLAD-based interface engineering plays a significant role in enhancing the optoelectronic performance of TiO₂ nanostructure-based photodetectors.