Enhanced Photodetection by Glancing Angle Deposited Vertically Aligned TiO2 Nanowires

The TiO
₂
thin film (TF) and nanowires (NWs) have been synthesized on Si substrate from pellets of pressed and sintered TiO
₂
powder using e-beam evaporation. The glancing angle deposition technique is adopted for the growth of TiO
₂
NWs. Field emission gun-scanning electron microscope analysis manifests the growth of vertically aligned NWs of length ~362 nm and diameters ranging from ~50 to ~290 nm. Energy dispersive X-ray analysis of NW sample shows the presence of Titanium (Ti), Oxygen (O
₂
) and Silicon (Si). The transmission electron microscope analysis also confirms successful growth of NWs and the selected area diffraction pattern shows the bright spot patterns from the crystals. X-ray diffraction of TF and NWs deposited at ambient temperature demonstrate multiple peaks from the anatase phase of TiO
₂
which supports the selective area diffraction pattern result. Under light exposure, the current densities for TF and NW device are ~5.11 and ~10.03 μA/cm
²
, respectively, at +6.5 V. A maximum photosensitivity of ~10 times is recorded for the NW device at -6.5 V. An excellent response with rise and fall times of ~0.16 and ~0.17 s respectively is observed during switching on and off of white light at +8 V for the NW device, which confirms promising photodetection applications.