Au/TiO₂ nanorod‐based Schottky‐type UV photodetectors

Abstract

TiO2 nanorods (NRs) were synthesized on fluorine‐doped tin oxide (FTO) pre‐coated glass substrates using hydrothermal growth technique. Scanning electron microscopy studies have revealed the formation of vertically‐aligned TiO2 NRs with length of ∼2 µm and diameter of 110–128 nm, homogenously distributed over the substrate surface. 130 nm thick Au contacts using thermal evaporation were deposited on the n‐type TiO2 NRs at room temperature for the fabrication of NR‐based Schottky‐type UV photodetectors. The fabricated Schottky devices functioned as highly sensitive UV photodetectors with a peak responsivity of 134.8 A/W (λ = 350 nm) measured under 3 V reverse bias. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Synthesis of TiO2 Nanorods for Schottky‐Type UV‐Photodetectors and Third‐Generation Solar Cells

“…Ag metal dots with 1 mm diameter were deposited on top of TiO 2 NRs through a copper shadow mask using thermal evaporation technique, the completed structure of which is given in Figure (b). The current density–voltage ( J–V ) characteristics of the Ag/TiO 2 NRs‐based Schottky PD in dark and under UV light illumination with wavelengths in the range of 300–420 nm was measured, as described elsewhere . Figure (c) shows the J–V characteristic of the PD under dark condition.…”

“…TiO 2 NRS were grown on fluorine‐doped tin oxide (FTO) coated glass substrates using hydrothermal technique, as detailed elsewhere . Once the TiO 2 NRs with optimum parameters, such as length, diameter, and density, were obtained, they were coated with a ∼50 nm thick silver (Ag) metallic top contacts via thermal evaporation technique to fabricate Ag/TiO 2 ‐NRs structured Schottky‐type UV PD.…”

“…Prior to the deposition of top contacts (Cu/Au), the device consisted of TiO 2 NRs decorated with CdTe layer was immersed in saturated CdCl 2 solution, prepared by dissolving 3 g of CdCl 2 powder in 110 mL methanol, which was kept for 10 s and then annealed at 450 °C on hot‐plate under N 2 gas flow for 30 min. The set‐up used to determine performance of the fabricated UV PD is reported elsewhere . The performance of the solar cell was determined from the current–voltage characteristics obtained under standard illumination conditions (AM 1.5).…”

“…Compared with photoconductors, photodiodes, such as Schottky‐type, offer significant advantages in terms of the speed of response and degree of responsivity. Although there are a large number of studies in literature on TiO 2 PDs, very few studies can be found on Schottky‐type ones …”

Enhanced photoresponse of conformal TiO2/Ag nanorod array-based Schottky photodiodes fabricated via successive glancing angle and atomic layer deposition

“…Additionally, larger aspect ratio of 1D nanostructures also contribute toward efficient trapping of the incident radiation via diffuse light scattering and enhanced optical absorption. 12,13 Previously, TiO 2 1D nanostructures fabricated by glancing-angle deposition (GLAD) 12,13 and hydrothermal growth technique 14,15 have been reported for the realization of highly sensitive Schottky type photodetectors. The observed enhanced photoresponsivity was attributed to the modification of oxygen species adsorbed at surface of TiO 2 nanorods (NRs) under illumination and trapped incident photons.…”