Search results for "chemical bath deposition"
showing 10 items of 11 documents
ZnO nanorod arrays fabrication via chemical bath deposition: Ligand concentration effect study
2010
A new ligand, N, N, N', N'-tetramethylethylenediamine, has been used to grow ZnO nanorods on silicon substrates via a two steps approach. A preliminary seeding on silicon substrates has been combined with chemical bath deposition using a Zinc acetate - N, N, N', N'-tetramethylethylenediamine aqueous solution. The used diamino ligand has been selected as Zn(2+) complexing agent and the related hydrolysis generates the reacting ions (Zn(2-) and OH(-)) responsible for the ZnO growth. The seed layer has been annealed at low temperature (<200 degrees C) and the ZnO nanorods have been grown on this ZnO amorphous layer. There is experimental evidence that the ligand concentration (ranging from 5 t…
Integration of Metal Organic Chemical Vapour Deposition and Wet Chemical Techniques to Obtain Highly Ordered Porous ZnO Nanoplatforms
2011
Large-area, highly ordered ZnO micropores-arrays consisting of ZnO nanotubes delimited by ZnO nanorods have been successfully fabricated and tested for protein sensing applications. ZnO seed layers have been deposited by Metal Organic Chemical Vapour Deposition and readily patterned by Colloidal Lithography to attain ZnO nanorods growth at selective sites by Chemical Bath Deposition. The used synthetic approach has been proven effective for the easy assembly of ZnO nanoplatforms into high-density arrays. Both patterned and unpatterned ZnO nanorods have been morphologically and compositionally characterised and, thus, tested for model studies of protein mobility at the interface. The pattern…
Progress in Violet Light-Emitting Diodes Based on ZnO/GaN Heterojunction
2020
Progress in light-emitting diodes (LEDs) based on ZnO/GaN heterojunctions has run into several obstacles during the last twenty years. While both the energy bandgap and lattice parameter of the two semiconductors are favorable to the development of such devices, other features related to the electrical and structural properties of the GaN layer prevent an efficient radiative recombination. This work illustrates some advances made on ZnO/GaN-based LEDs, by using high-thickness GaN layers for the p-region of the device and an ad hoc device topology. Heterojunction LEDs consist of a quasicoalesced non-intentionally doped ZnO nanorod layer deposited by chemical bath deposition onto a metal&ndash
Effects of Metal-Organic Chemical Vapour Deposition grown seed layer on the fabrication of well aligned ZnO nanorods by Chemical Bath Deposition
2011
Well aligned, long and uniform ZnO nanorods have been reproducibly fabricated adopting a two-steps Metal-Organic Chemical Vapour Deposition (MOCVD) and Chemical Bath Deposition (CBD) fabrication approaches. Thin (<100 nm) ZnO buffer layers have been seeded on silicon substrates by MOCVD and ZnO layers have been subsequently grown, in form of well textured nanorods, using CBD. It has been found that the structure and thickness of the seed layer strongly influence the final morphology and the crystal texturing of ZnO nanorods as well as the CBD growth rate. There is, in addition, a strong correlation between morphologies of CBD grown ZnO nanorods and those of the seed layer underneath. Thus, …
Synthesis and photoluminescence properties of hybrid 1D core–shell structured nanocomposites based on ZnO/polydopamine
2020
In the present work, we report on the modelling of processes at the zinc oxide and polydopamine (ZnO/ PDA) interface. The PDA layer was deposited onto ZnO nanorods (NRs) via chemical bath deposition. The defect concentrations in ZnO before and after PDA deposition were calculated and analysed. The ZnONRs/PDA core–shell nanostructures were studied by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier-transform infrared (FTIR) spectroscopy, photoluminescence (PL) measurements, and diffuse reflectance spectroscopy. The TEM and electron energy loss spectroscopy (EELS) measurements confirmed the conformal coating of PDA, while the PL emission from ZnO and ZnONRs/P…
Photoluminescence transient study of surface defects in ZnO nanorods grown by chemical bath deposition
2015
Two deep level defects (2.25 and 2.03 eV) associated with oxygen vacancies (Vo) were identified in ZnO nanorods (NRs) grown by low cost chemical bath deposition. A transient behaviour in the photoluminescence (PL) intensity of the two Vo states was found to be sensitive to the ambient environment and to NR post-growth treatment. The largest transient was found in samples dried on a hot plate with a PL intensity decay time, in air only, of 23 and 80 s for the 2.25 and 2.03 eV peaks, respectively. Resistance measurements under UV exposure exhibited a transient behaviour in full agreement with the PL transient, indicating a clear role of atmospheric O-2 on the surface defect states. A model fo…
Low-cost high-haze films based on ZnO nanorods for light scattering in thin c-Si solar cells
2015
Light scattering from ZnO nanorods (NR) is investigated, modeled, and applied to a solar cell. ZnO NR (120-1300 nm long, 280-60 nm large), grown by low-cost chemical bath deposition at 90 degrees C, exhibit diffused-to-total transmitted light as high as 70% and 30% in the 400 and 1000 nm wavelength range, respectively. Data and scattering simulation show that ZnO NR length plays a crucial role in light diffusion effect. A transparent ZnO NR film grown on glass and placed on top of a 1 mu m thick c-Si solar cell is shown to enhance the light-current conversion efficiency for wavelengths longer than 600 nm. (C) 2015 AIP Publishing LLC.
Fabrication of CZTSe/CIGS Nanowire Arrays by One-Step Electrodeposition for Solar-Cell Application
2021
The paper reports some preliminary results concerning the manufacturing process of CuZnSnSe (CZTSe) and CuInGaSe (CIGS) nanowire arrays obtained by one-step electrodeposition for p-n junction fabrication. CZTSe nanowires were obtained through electrodeposition in a polycarbonate membrane by applying a rectangular pulsed current, while their morphology was optimized by appropriately setting the potential and the electrolyte composition. The electrochemical parameters, including pH and composition of the solution, were optimized to obtain a mechanically stable array of nanowires. The samples were characterized by scanning electron microscopy, Raman spectroscopy, and energy-dispersion spectros…
Fabrication and characterisation of ZnO nanostructures: from nanoscale building blocks to hybrid nanomaterials - towards emerging technologies in sen…
2012
Metal oxide nanostructures characterized by multiple morphologies and structures are at the forefront of applications driven nanotechnology research. In particular, they represent a versatile solution for performance enhancement and applications in multifunctional devices and offer distinct advantages over their bulk counterparts. The current state in ZnO nanomaterials research and its impact in nanotechnology and modern engineering are discussed through the lens of con-tinuing technological advances in synthetic techniques allowing to obtain the material with predefined specific set of criteria including size, functionality, and uniqueness. Aim of this research activity is fabrication and …
Chemical Bath Deposition as a Simple Way to Grow Isolated and Coalesced ZnO Nanorods for Light-Emitting Diodes Fabrication
2018
A way to grow and characterize isolated and coalesced ZnO nanorods on $p$ -GaN/sapphire structure is presented. Chemical bath deposition can be used to grow ZnO nanorods of device-quality, simply controlling the duration time of the growth process and the concentration of the nutrient solution in the bath. Increasing the duration of the process, as well as the concentration of the solution, leads to compact and sound layers instead of separated nanorods. However, too high concentrations stop the growth process. Light-emitting diodes fabricated on these ZnO-p-GaN heterostructure have a peak of electroluminescence at 400 nm and exhibit interesting electrical and optical properties. Optical po…