Enhancement of Broad Light Detection Based on Annealed Al-NPs Assisted TiO2-NWs Deposited on p-Si by GLAD Technique

In this paper, broad band light detection properties of annealed vertically aligned TiO
₂
Nanowires (NWs) and Al Nanoparticles assisted TiO
₂
NWs (Al-NPs-TiO
₂
-NWs) fabricated on Si substrates using indigenous glancing angle deposition system are investigated. The XRD spectrum manifests that the grain size of polycrystalline anatase TiO
₂
increases after annealing and also confirms the presence of small Al nanocrystals in the sample supporting the TEM result. The optical absorption spectra analysis of both as-deposited and annealed Al-NPs-TiO
₂
-NWs reveals that the incorporation of Al-NPs in TiO
₂
-NWs enhances the photon absorption in UV and visible region as compared to annealed TiO
₂
-NWs. The I-V characteristics of Al/TiO
₂
-NWs/p-Si and Al/Al-NPs-TiO
₂
-NWs/p-Si photodetectors show the rectifying behavior due to p-n junction formation at the interface of TiO
₂
and p-Si. It is interesting to observe that Al/Al-NPs-TiO
₂
-NWs/p-Si based device gives better photosensitivity as compared to Al/TiO
₂
-NWs/p-Si under visible light illumination at reverse bias condition which may be due to SPR effect of Al NPs. This result confirms that the growth of Al-NPs-TiO
₂
-NWs using this simple technique may be applicable for broad band light detection for different optoelectronic applications.