Development of highly sensitive UV photodetector based on chevronic TiO2 thin film using simple oblique angle deposition technique

Abstract

Chevronic TiO₂ thin film (CTTF)-based ultraviolet (UV) photodetector was fabricated on p-type silicon (Si) substrate using oblique angle deposition (OAD) technique inside an electron beam evaporation chamber. A conventional TiO₂ thin film (TTF) was also fabricated to compare the performances of the UV photodetectors. The field emission scanning electron microscopy (FE-SEM) image verified the porous nature of the successfully fabricated chevronic TiO₂ nanostructures (~ 236 nm), while the X-ray diffraction (XRD) analysis confirmed the amorphous nature of both the CTTF and TTF samples. Optical absorption of CTTF showed enhancement of absorption intensity between ~ 380 nm and 800 nm wavelength than the conventional TTF. An energy bandgap of ~ 3.31 eV was observed from the Tauc plot of the CTTF. The CTTF- and TTF-based photodetector devices were analyzed under UV illumination (~ 390 nm) at a biasing of − 2 V. Superior performances of the CTTF-based photodetector in terms of photosensitivity (~ 7.65), responsivity (~ 1.79 A/W), detectivity (~ 1.40 × 10¹² Jonnes), noise equivalent power (~ 2.01 × 10^–12) and external quantum efficiency (5.69) were achieved compared to the conventional TTF and other previously reported photodetectors.