Electrochemical growth of ZnO nanorod arrays onto transparent conductive IZO:Ga substrates

Abstract

Large-area vertically orientated and high-density ZnO nanorod arrays (NRAs) have been electrochemically grown directly onto IZO:Ga thin film transparent conductive oxide (TCO) substrates. For the sake of comparison, ZnO NRAs have also been electrodeposited onto conventional TCO/glass substrates (F-doped SnO 2 (FTO) and Sn-doped In 2 O 3 (ITO). The morphological and structural properties of the resulting ZnO NRAs have been studied. The nucleation and growth mechanism (NGM) that governs the electrochemical growth of these ZnO nanostructures onto these TCO substrates were investigated, demonstrating that the IZO:Ga thin film triggers the orientated and structured growth of ZnO nanorods. ZnO nanorods of ca. 225 nm, 256 nm and 259 nm in diameter and ZnO NRAs densities values of 2.05 × 10 8 cm −2 , 2.27 × 10 8 cm −2 and 7.83 × 10 8 cm −2 have been obtained when deposited onto these FTO, ITO and IZO:Ga thin film substrates, respectively. NGM study results indicate that onto FTO and ITO after an initial current decay (following a Cottrell law), a 3D instantaneous nuclei formation limited by lattice incorporation takes place. Whereas onto the IZO:Ga substrate, at the early stages a new contribution 3D instantaneous nucleation under diffusion control, appeared, revealing that these densely packed IZO:Ga nanocrystals may act as homo-epitaxial nucleation sites.

Electrochemical Synthesis of Zinc Oxide Nanostructures on Flexible Substrate and Application as an Electrochemical Immunoglobulin-G Immunosensor

“…Obviously, this is reflected in the morphology of the zinc oxide and confirms our previous discussions. Similar results and conclusions were also gained by Dalchiele et al [104]. For applied cathodic potentials lower than −0.8 V, the deposition rate is low, consequently the nucleation rate is low.…”

“…The high intensity diffraction peaks at 34.3, 36.2 and 62.9 • match with the ZnO hexagonal wurtzite structure (ICDD card 36-1451) [111,114]. As reported in [104], the high intensity of (002) diffraction plane is attributed to the presence of wellshaped c-axis oriented hexagonal columns. The presence of rGO cannot be verified by XRD, because its pattern is characterized by the presence of only a broad band located at about 26 • , thus overlapped onto the main peak of the PET substrate.…”

“…The electrodeposition process of ZnO, introduced by Izaki et al [32], has several advantages such as low cost, environmental friendly and easy scalability. The deposition of ZnO is an electrochemically induced precipitation process [47,104] and occurs from an aqueous solution of zinc salts (ZnCl 2 or Zn(NO 3 ) 2 ). Depending on the deposition solution, dissolved oxygen (reaction 1) or nitrate ions (reaction 2) or both, react producing OH − close to the electrode/electrolyte interface.…”

Insights into Effects of Annealing Environment on the Changes in Structural Properties and Electrochemical Performance of Nitrogen‐Doped Zinc Oxide Nanosheets

“…The Zn LMM of XPS spectra indicates that Auger peaks of Zn exist in ZnO in the ranges 475–510 eV, which are attributed to free‐state Zn from interstitial position. [ 36 ] Careful observation shows that Zn 2p intensity increased and Zn LMM reduced in the case of A75 and V75 than undoped samples. The Zn 2 p doublet separations, as shown in Figure 7d, are around 23.0–23.1 eV, which is in good agreement with previously reported values for zinc ions.…”

Controlled Growth of Semiconducting ZnO Nanorods for Piezoelectric Energy Harvesting-Based Nanogenerators

“…The seed-induced hydrothermal method was developed by Vayssieres et al [ 120 ] to produce ZnO nanorod arrays on silicon and glass substrates in high-pressure autoclaves. The electrochemical deposition has recently been used to grow ZnO nanorod arrays on transparent conductive substrates [ 121 ]. However, certain controlled synthesis methods effectively increase the orientation, shape, and crystallinity of ZnO nanostructures [ 48 , 122 , 123 , 124 ].…”