Synthesis of titanium nitride thin films deposited by a new shielded arc ion plating

Thin films of titanium nitride (TiN) were deposited on stainless steel substrates by a modified deposition technique, double-layered shielded arc ion plating with vicarious circular holes (DL-SAIP). The results show that the TiN film with the distance of 10 mm between the double-layered shield plates had the least droplets. The deposition rate of the films prepared with the new technique was more homogeneous than that of all the other shielded arc ion plating. The film/substrate adhesion and microhardness values of the TiN films were higher than 40 N and 18 GPa, respectively. Thus such TiN thin films can be expected in applications.     

Pulsed laser deposition process of PLZT thin films using an infrared Nd:YAG laser

Pulsed laser depositions of PLZT thin films were performed using an Nd:YAG (1064 nm) laser. The growths took place in vacuum or in an oxygen background. Room temperature and 500 °C were the used substrate temperatures. The X-ray diffraction analysis revealed a preferential crystallographic orientation in the films grown at room temperature in vacuum. Such result is discussed. The velocity distribution functions of the species in the plasma plume were obtained from a time of flight study using optical emission spectroscopy. The maximums of these distributions functions fall around 10⁶ cm/s, equivalent to an energy range of 18-344 eV. Ionic species of heavy elements (like lead) achieved higher velocities than other lighter species. This result is linked to the creation of an accelerating spatial charge and to the thermal nature of the target material extraction that allows some elements to be released first than others. Chemical state variations of the elements present in the films were analyzed. Under these different growing conditions, lead chemical states varied the most.     

Pulsed laser thin film growth of di-octyl substituted polyfluorene and its co-polymers

Matrix-assisted pulsed laser deposition (PLD) allows a controlled layer-by-layer growth of polymer films. Di-octyl substituted polyfluorene (PF8) and its copolymers were deposited as thin films using matrix-assisted PLD by employing a KrF excimer laser with a fluence of 125 mJ/pulses. The optical and structural properties of these films are compared with spincoated films via Raman spectroscopy, absorption and photoluminescence. The Raman spectra of both PLD and spincoated films are similar indicating that the polymer films deposited via PLD maintain their molecular structure. Both the spincoated and the PLD grown PF8 films that were cast from toluene show the presence of the β phase. Benzothiadiazole substituted PF8 (F8BT) and butyl phenyl-substituted PF8 (PFB) PLD grown films show a slightly broader emission compared to the spincoated films, which is attributed to an enhanced intermolecular interaction in the PLD grown thin films.     

Laser induced reverse transfer of gold thin film using femtosecond laser

Laser induced reverse transfer (LIRT) has been executed first time using a Mega Hertz pulse frequency femtosecond laser radiation under ambient conditions. Research has been conducted to understand the evolution of deposited structures with regard to pulse energy. Solid deposition of gold could be deposited on quartz substrate only if pulse energy falls within a certain range. For the experiment conducted in this work, it is 36-40 nJ. For energies above this range, crests appear in the middle of the deposition. There is a threshold in maximum applicable pulse energy, 82 nJ in this exepriment, beyond which further increase in pulse energy results in only traces of deposited material. Results also show that the width of deposited line increases with the increase in pulse energy and decreases with the increase in scan speed. These observations have been explained using the dynamics of ablated plume.     

Laser annealing process of ITO thin films using beam shaping technology

In this study, we develop a laser annealing system for In₂O₃Sn (ITO) to carry out heat treatment on oxides with high melting temperature on substrates with low melting temperature. It is known that the working temperature of traditional heat treatments is usually limited by the melting point of the substrate materials. To overcome this problem, we apply a laser annealing technique to modify the film properties, and to measure the electrical and surface properties, we use Hall measurement, a four-point probe, and an atomic force microscope in our experiment. We will discuss how the annealing is affected by the laser machining parameters, including the beam profile, intensity distribution, laser spot overlap, and laser operation mode. We will further show through experimental results that the beam profile greatly affects the surface roughness of the ITO films. With the use of a uniform beam profile with proper laser intensity, the surface roughness and the sheet resistance of the ITO films can be reduced from 23 nm to 4.2 nm and from 417 Ω/sq to 400.4 Ω/sq, respectively.     

Electrosynthesis and characterization of CdSe thin films: Optimization of preparative parameters by photoelectrochemical technique

CdSe thin films have been electrodeposited potentiostatically onto stainless-steel and fluorine-doped tin oxide-coated glass substrates from an aqueous acidic bath using cadmium acetate ((CH₃COO)₂Cd·2H₂O) as a Cd ion source. Preparative parameters such as deposition potential, solution concentration, bath temperature, pH of the electrolytic bath and deposition time have been optimized by using photoelectrochemical (PEC) technique to obtain well adherent and uniform thin films. The electrodeposits were dark brown in colour. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques. XRD studies reveal that films are polycrystalline, with hexagonal crystal structure. SEM shows that the films are compact, with spherical grains. Optical absorption studies reveal that the material exhibits a direct optical transition having band gap energy ∼1.72 eV. PEC study shows that the films are photoactive.     

Deposition of ZnS thin film by ultrasonic spray pyrolysis: effect of thickness on the crystallographic and electrical properties

Zinc sulfide (ZnS) thin films have been deposited on Si (1 0 0) substrate using ultrasonic spray pyrolysis. X-ray diffraction (XRD) analysis revealed that the films are (0 0 2) preferentially oriented with c-axis-oriented wurtzite structure. The crystallinity has been found to improve with film thickness in the 180–6000 nm range. Film structure has been analyzed by XRD, scanning electron microscope, FTIR, and Raman spectroscopies, while the stoichiometry has been verified by energy-dispersive spectroscopy and particle-induced X-ray emission techniques. Electrical properties of the grown films were characterized by current–voltage and capacitance–voltage measurements where, the films show better conducting behavior at higher thickness.