Papers by Keyword: Seed Layer

Abstract: Vertically aligned nanorods ZnO have been deposited hydrothermally on the pre-coated ZnO seeded-glass substrates. Enhanced vertical alignment is achieved as a result of combined film post-treatments. Dipped-drawn and immersed-washing the as-synthesized ZnO films in water as well as quenching of the hydrothermal were proposed to hinder excessive deposition and engineer the growth of ZnO nanorods. The XRD patterns shows suppressed growth of ZnO crystallite along (101) with increased textural coefficients on (002), TC₀₀₂, from 3.94 to 5.23. Dense vertically aligned bundles of ZnO nanorods may reach up to 0.75 μm length. Bandgap energy of the resulted ZnO nanorod thin films were ranging from 3.69 to 3.79 eV, wider than those of bulk ZnO. Hydrothermal technique with simple post-treatments of immersed-washing and hydrothermal quenching has offered robust and efficient method to prepare vertically-aligned 1-D ZnO nanorods potential as photoanodes for dye-sensitized solar cells.

Abstract: The properties and performances of Zinc Oxide (ZnO) film have made the material spread widely in several applications such as in providing energy to consumers in which it is harvest energy from the sun rays. By using hydrothermal method in order to fabricate ZnO films is one of the process that consume less energy and lower temperature compare to the other methods. In this research, the seed layer of ZnO was deposited on Fluorine doped Tin Oxide (FTO) substrate and heat treated at 100 °C for 10 min prior to the hydrothermal growth. Hydrothermal growth temperature was varies at 70 °C, 90 °C and 110 °C for 12 hours. The ZnO-coated FTO films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy disperse spectroscopy (EDS). The I-V characteristic of the ZnO-coated FTO films was characterized with solar simulator. The experimental results reveal that the hydrothermal growth temperature exerts a strong influence on the properties of the ZnO-coated FTO films. The effects of the hydrothermal growth temperature are discussed.

Abstract: Highly oriented and well-aligned ZnO nanorod arrays were synthesized by low-temperature solution phase method on copper substrate under different conditions. Results illustrated that dense ZnO nanorods were vertically and uniformly distributed on the substrate. The effects of precursor concentration, growth temperature and time on the morphologies of nanorod arrays were investigated systematically. It is demonstrated that the controllable growth of well-aligned ZnO nanorods can be realized by readily adjusting the preparation parameters. The high quality ZnO nanorod arrays could be achieved via the chemical approach at low temperature.

Abstract: This paper demonstrates the deposition of barrier layers and seed layers in TSV for 3D package. The high aspect ratio through silicon via sputtering process uses the magnetron-sputtering of Au. In order to achieve the continuous coverage of thin film on the sidewall and bottom of vertical microvias, the sputtering and anti-sputtering process was optimized. The impact of thickness of the seed layer and the gas pressure of the chamber on the coverage of the seed layers are discussed. The continuous seed layers and barrier layers on in the micro-vias with aspect ratio 3.5 can be achieved at low cost.

Abstract: Polycrystalline magnetite films with the thickness of 50 nm were grown on SiO₂/Si(001) surface by the reactive deposition of Fe in O₂ atmosphere using various preparation ways of the formation of iron oxide seed layer. The seed layers were formed by the deposition and oxidation of 3 nm Fe layer at different thermal conditions. It was found that polycrystalline magnetite films grown with the use of seed layer have [110] texture and are characterized by increase of the squareness of magnetic hysteresis loop. Structural analysis of magnetite films and predeposited seed layers was studied by RHEED.

Abstract: We demonstrate that single crystalline ZnO nanowires with large length/diameter ratio are successfully grown on Si, glass, and Si with ZnO seed layer via simple thermal vapor deposition, without introducing any catalyst or additive. In this work, we study impact of growth conditions such as growth temperature, substrates, and ZnO seed layer on morphology and photoluminescence properties of ZnO nanowires, in terms of systematic characterizations. The investigations show that the growth temperatures have substantial effect on the morphology of ZnO nanowires, while substrates have low impact. And 700 °C is believed to be the optimized growth temperature among the series of temperatures. Moreover, ZnO seed layer plays an important role in the uniformity and reproducibility of ZnO nanowires growth. PL measurements for the ZnO nanowires exhibit two emission bands including a UV emission and a blue emission, respectively. Finally, the growth behavior of the ZnO nanowires is discussed based on the VS growth mechanism. Our resluts have made a positive progress toward improving control of the morphology of ZnO nanowires.

Abstract: In this study, we reported the fabrication and characterization of a nano hetero junction (NHJ) structure which is synthesized by a 2-step hydrothermal growth (HTG) method. The zinc oxide (ZnO) nano rods (NRs) were grown by the 2-step HTG onto p-type nickel oxide (p-NiO) film e-beam deposited glass substrate to form n-ZnO-NRs/p-NiO NHJs. The electrical properties of the n-ZnO-NRs/p-NiO NHJs show a rectifying behavior of a p-n junction. The optoelectronic properties of the n-ZnO-NRs/ p-NiO NHJs under UV light (366 nm) light with good sensitivity were presented.

Abstract: Using a novel approach with low-cost and simple-equipment, the hydrothermal growth of ZnO nanowires array films on glass substrates was carried out after pre-coated ZnO nanoparticle precursor as crystalline nuclei. The physical phase and morphology of the ZnO thin films with nanowires structure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The results indicate that ZnO films with nanowires array are hexagonal symmetry and highly oriented crystalline array films, which grows along c-axis of ZnO. The diameter of the nanowires is about 60 nm. A strong UV peak, a weak blue band and a weak green band at 399, 469 and 569 nm is observed, respectively, in the photoluminescence (PL) spectra.

Abstract: A novel method for growing highly-crystalline 3C-SiC on an oxide release layer via a poly-Si seed layer is reported. Silicon carbide’s potential role as a ubiquitous material for MEMS fabrication lies in its dual role as an electronic and mechanical material. Unfortunately, due to residual stresses and crystal defects stemming from the large lattice constant mismatch and the thermal expansion coefficient difference between SiC and Si, the use of SiC in Si-based MEMS fabrication techniques has been very limited. The growth of 3C-SiC on a poly-Si seed layer deposited on oxide on (111)Si substrates (i.e., p-Si/ SiO2/(111)Si) provides an alternative fabrication method to expensive, traditional SOI bonding techniques for producing free-standing 3C-SiC MEMS structures. 3C-SiC grown with a poly-Si seed layer on SiO2 should experience reduced residual stress and far fewer defects due to the compliance of the SiO2 layer. Although poly-Si is utilized as a seed layer in this process, a well-ordered monocrystalline 3C-SiC layer was achieved and the process and film properties reported.

Abstract: Pb(Zr, Ti)O3 thin films were successfully prepared on (111)Pt/IrO2/SiO2/(100)Si substrates using SrTiO3 seeds at 290 oC by RF inductive heating type and 350 oC by resistive heating type metalorganic chemical vapor deposition method (MOCVD), respectively. The SrTiO3 was chosen as seed layers and prepared by pulsed laser deposition method. The crystal structures and orientations of SrTiO3 seeds were changed by deposition temperature. In the case of preparation with RF inductive heating MOCVD, the remanent polarization (2Pr) and coercive field (2Ec) were 42 μC/cm2 and 256 kV/cm, respectively.