Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

Abstract

Here, we report on how the energy band diagram of a nanostructured semiconductor-metal interface aligns in accordance with semiconductor morphology. Electrochemically, titanium metal is anodized to form titanium dioxide nanotubes, which forms a junction with the free Ti substrate and this junction forms a natural Schottky barrier. With reduced dimensionality of the nanotube structures (lower wall thickness), we have observed band edge movements and band gap quantum confinement effects and lowering of the Schottky barrier. These results were corroborated with the help of cyclic voltammetry, ultraviolet-visible spectrometry, and impedance analysis. Current voltage analysis of the Schottky barrier showed a lowering of the barrier (by 25 %) with reducing dimensionality of the nanotube structures. At externally applied voltages higher than the Schottky barrier, charges can travel along the nanotubes and reside at an interface between the nanotubes and a high-κ dielectric. This property was utilized to develop high surface area solid-state capacitors.

Cold sprayed WO3and TiO2electrodes for photoelectrochemical water and methanol oxidation in renewable energy applications

“…45 For the cold sprayed Ti/TiO 2 metalsemiconductor junction a Schottky contact is assumed in the literature. 46,47 However, there is almost no barrier at the ) at a bias of 1 V vs. NHE.…”

Design and development of an integrated device consisting of an independent solar cell with electrical storage capacity

“…The I–V curve is shown in Figure (a), which indicated a barrier breakdown voltage of 0.28 V (the Schottky barrier potential) which in this case was lower than the open‐circuit voltage of the PV ( V oc = 0.42 V, J sc = 970 μA cm −2 ). As the contact is between a metal (titanium) and a wide band gap semiconductor (TiO 2 ), we have separately investigated the nature of this interface in detail . We had electrochemically determined the band edge positions (in flat band condition) of TiO 2 nanotube film on the electron volt scale and in comparison to the work function ϕ m of Titanium metal (4.33 eV); the conduction band edges of the TiO 2 nanotube film are far placed thus giving rise to a Schottky potential barrier.…”

Manipulating Electrical Properties of Nanopatterned Double-Barrier Schottky Junctions in Ti/TiOx/Fe Systems

“…It results from different growth processes, where nanotubes form, leading to size confinement, different crystallization mechanisms, and changes in intrinsic conductivity. The most prominent change lies in the existence of the native Schottky barrier layer at the ATO/Ti interface, which is not observable in thermally grown titanium oxide/titanium systems …”

“…The most prominent change lies in the existence of the native Schottky barrier layer at the ATO/Ti interface, which is not observable in thermally grown titanium oxide/titanium systems. 59 The energy levels of the metal and semiconductor are in a nonequilibrium state before contact. The Fermi level of titanium oxide nanotubes is higher than that of the titanium and iron layers, with a difference of 0.3 and 0.7 eV, respectively.…”