Metal organic chemical vapor deposition of ZnO from β‐ketoiminates

ZnO is a high‐mobility electron conductor being considered for high‐throughput electronics in flexible and transparent formats. We demonstrated the Zn β‐ketoiminate system, based on acetylacetimine with N‐propyl, isopropyl, and butyl groups, as a vehicle for preparing ZnO thin films for electronic applications. Surface carbon was a primary impurity, and the precursors studied afforded films with the lowest surface carbon contamination at deposition temperatures near 400°C. Thermal annealing of the films reduced the surface carbon content and afforded semiconducting materials. Annealing also gave larger‐grained, better connected films. Thinner films were associated with semiconducting as opposed to ohmic behavior; such films will be adaptable for transparent logic circuits. Copyright © 2012 John Wiley & Sons, Ltd.     

Luminescence properties of Cu‐ion‐implanted and annealed ZnO thin films deposited by chemical vapor deposition and pulsed laser deposition

Ion implantation techniques were used to study the effect of an MgO additive on the luminescence properties induced by Cu in ZnO thin films. Cu ions (accelerating voltage of 75 keV, dose of 4.5 × 10¹⁴ ions/cm²) were implanted at room temperature in nondoped and Mg‐doped ZnO thin films. After annealing, emissions in the visible region originating from Cu phosphor were observed at 510 nm in CVD‐ZnO and at 450 nm in Mg‐doped ZnO (MZO) thin films. The Cu depth profile shows distortion in the low‐concentration region of CVD‐ZnO. After the annealing, the Cu implant was homogenized in thin films, and then the Cu concentration was determined to be 1.5 × 10¹⁹ ions/cm³ in CVD‐ZnO and 5.6 × 10¹⁸ ions/cm³ in MZO thin films. Copyright © 2005 John Wiley & Sons, Ltd.     

Effects of temperature on the properties of TiO2 photocatalysts prepared by the chemical vapor deposition (CVD) method

In this study, a TiO₂ film was prepared in an annular reactor by the chemical vapor deposition (CVD) method. Results indicated that anatase crystals were formed, except for at a deposition temperature of 200°C without calcination. At a calcination temperature of 850°C, anatase crystal was the major species formed with a small amount of rutile crystals. After conducting a photocatalytic reaction of toluene, the best activity was found with a preparation temperature of 350°C for the deposition, and 550°C for calcination.     

Study on the anti‐reflection and structure evolution of hydrogenated amorphous carbon grown by plasma chemical vapor deposition

In this work, the interrelation between the anti‐reflective property and the component, especially the sp² content, was studied. The results showed that the refraction index n increased from 2.2 to 3.3 with the direct current negative bias increasing. The reflection result R successful fall by 11.9% because of the existence of hydrogenated amorphous carbon anti‐reflective coatings. Both the refraction index and reflectivity decreasing correspond to a more graphitic microstructure character. Moreover, the optical property evolution of the films was explained by the chemical vapor deposition mechanism based on the ion sub‐plantation model and two‐phase model. Copyright © 2014 John Wiley & Sons, Ltd.     

Synthesis of electro‐active membranes by chemical vapor deposition (CVD) process

In the past two decades, many research is being carried out on coating of textile membranes with conductive polymers. In order to functionalize the textile membranes, coating of different intrinsically conductive polymers can be applied on these membranes through appropriate coating techniques like electrochemical polymerization, wet chemical oxidation and chemical vapor deposition (CVD). Noticeably, CVD process is one of the most suitable and environment friendly technique. In this research, microporous polyester and polytetrafluoroethylene (PTFE) membranes were coated with conductive poly(3,4‐ethylenedioxythiophene) (PEDOT) by CVD process in the presence of ferric(III)chloride (FeCl₃) used as an oxidant. Polymerization of PEDOT on the surface of membranes and pore size was examined by optical microscope and scanning electron microscopy (SEM). Structural analysis investigated with ATR‐FTIR, which revealed the successful deposition of PEDOT on membranes without damaging their parent structures. The amount of PEDOT in PEDOT‐coated polyester and PTFE membranes was explored with the help of thermogravimeteric analysis. Electrical resistance values of PEDOT‐coated membranes were measured by two probe method. The effect of different electrolyte solutions such as, distilled H₂O, Na₂SO₄, HCl, and H₂SO₄ on electrical properties of produced conductive membranes was investigated after dipping for certain period of time. It was found that membranes dipped in H₂SO₄ show very low electrical resistance values, i.e. 0.85 kΩ for polyester membrane and 1.17 kΩ for PTFE membrane. The obtained PEDOT‐coated electro‐active membranes may find their possible utility in fuel cells, enzymatic fuel cells, and antistatic air filter applications. Copyright © 2014 John Wiley & Sons, Ltd.     

Palladium nanoparticles supported on SiO2 by chemical vapor deposition (CVD) technique as efficient catalyst for Suzuki–Miyaura coupling of aryl bromides and iodides: selective coupling of halophenols

Nanoparticles of palladium were supported on SiO₂ by chemical vapor deposition technique. The obtained Pd nanocatalyst was characterized by various techniques. This catalyst was found to be very efficient for the selective cross‐coupling of hydroxyl‐substituted aryl iodides and bromide with arylboronic acids in water at room temperature to produce the corresponding hydroxyl‐substituted biaryls. Coupling of phenylboronic acid with aryl iodides and bromides carrying substituents other than hydroxy group was also performed efficiently in refluxing ethanol. Copyright © 2012 John Wiley & Sons, Ltd.