This paper evaluates the effect of parametric variation on the structure, surface composition and tribological properties of reactive RF-magnetron sputter deposited ZrN/ Zr2ON2 thin films. The properties of the films were investigated with respect to Ar: N2 flow rate, and power coupled to the plasma. X-ray photoelectron spectroscopy (XPS) revealed the presence of both the Zr2ON2 and ZrO2 stoichiometric components on the surface. Also, coupled power beyond 100 W promotes the formation of Zr2ON2 on the film surface. That's why samples having thickness as low as 101-106 nm exhibit lower COF values 0.42-0.46 owing to the dominant presence of lubricating ZrO2 phase in the surface layer. Grazing angle X-ray (GIXRD) diffractogram exhibit that in the bulk, cZrN (311) and c-Zr2ON2 (440) phases are dominant. With increased power beyond 100 W, the (222) orientation of the Zr2ON2 phase also becomes significant, owing to enhanced reaction rate between the sputtered Zr and reactive gas atoms. Tribological studies show that the sample with the lowest surface roughness (S5) (-114 nm) has the highest specific wear rate (-1.26 x10- 3 mm3/ Nm). Colour of the films changed with applied power from grey at 50 W, to brownish yellow at 100 W, blue at 150 W, and golden yellow at 200 W. The films exhibited long term stability after 18 months of deposition, in terms of adhesion and colour, upon exposure to ambient condition.

Boron carbide films deposited by PECVD are subjected to post deposition vacuum annealing and plasma treat-ment for investigation of changes in the structure, linear and non-linear optical properties of the films. Decon-volution of core level XPES spectra of B1s, C1s and O1s indicates changes in the surface chemical states of the constituent atoms after post deposition treatments. Particle size estimated from XRD spectrum is found increasing from 135 to 140 nm after annealing. Envelop method is used to estimate refractive index, extinction co-efficient, and thickness from their measured optical transmission spectra in VIS-NIR region (400-1400 nm). The refractive index value is found to be 1.619, highest for the vacuum annealed boron carbide film. Direct and indirect optical bandgap remains same after vacuum annealing (Eg = 2.84), the plasma treatment causes a slight decrease in the bandgap. 5% decrease in film thickness is observed after post deposition annealing and plasma treatment owing to film densification. Energy loss in the medium measured in terms of tan delta and ELF's reveals that the vacuum annealing of the film reduces the electromagnetic and electron energy loss in the film. Non -linear refractive index estimated using Ticha and Tichy relation exhibits similar trend as the linear refractive index spectra.

Traditional disinfection methods against pathogens have numerous shortcomings, and inventive methods like cold plasma are required for virus inactivation. Here, an atmospheric pressure 13.56 MHz radio-frequency hollow cathode (RF–HC) cold plasma device has been used to build a cold plasma sterilization device, and its virucidal activity is assessed against P2 bacteriophage, a model surrogate for pathogenic viruses. The heart of this device contains a three-layered sterilization chamber which is a rectangular parallelopiped of 42 × 32 × 30 cm 3 . Optimization experiments were performed to make each corner of this chamber completely virus free after cold plasma treatment. This two-pronged study was conducted to establish the requirement of minimum vol. % H 2 O 2 in minimum time for the complete elimination of phages inside this sterilization chamber even when plasma is not in the direct line of sight. In initial experiments, the effect of the direct plasma line of sight was seen as the top and bottom layers showing less phage killing as compared to the middle of the sterilization chamber. Complete sterilization of bacteriophage, in all the three layers inside the sterilization chamber, was achieved by plasma treatment with 6% H 2 O 2 for 10 min in 80 watts of plasma operating power. It was also seen that 6% H 2 O 2 mist alone is not sufficient to provide a high degree of sterilization, and normal water mist combined with cold plasma can provide a higher level of sterilization at each corner of the chamber.

Radio-Frequency Plasma Enhanced Chemical Vapour Deposition (RF-PECVD), and Pulsed Laser Deposition (PLD) techniques were used to deposit boron carbide (BxC) thin films. Films were investigated to compare crystallinity, chemical composition, optical properties, and residual stress. X-ray diffraction analysis revealed that the film deposited by PLD was amorphous, while PECVD technique yielded crystalline BxC film. PLD technique provided films with better stoichiometric purity with B4C being the most dominant phase, as observed in XPS spectra. However, super-stoichiometric phase (BxC (x > 4)) was dominant in PECVD film. Moreover, the PECVD film had greater adhesion (Lc(3) similar to 29.5 N), hardness (similar to 2798 HK), and lubricity (COF similar to 0.03) compared to PLD deposited film. Optically, PECVD deposited film have higher value of refractive indices (1.82 at 600 nm) and lower extinction coefficient. Finally, residual stress measured via substrate curvature method revealed that for PLD 400 C film, the stress was compressive in nature while the same for PECVD -100 V film was tensile, with 10 times less in magnitude. Ultimately, this study provides the user with opportunity to weigh the advantages and disadvantages of PECVD and PLD techniques for deposition of functional BxC films.

Plasma is probably the most underused tool applied for nuclear waste management. To study the feasibility of putting this technology in practice, a non-thermal microwave based atmospheric pressure plasma jet (APPJ) had been developed. The device was characterized by spectroscopic technique prior to its actual deployment inside glove box to narrow down its operational regime and also tested on Ta, a known surrogate of Pu which showed its efficacy in etching. The device was then used for removal of Pu based synthetic radioactive wastes inside radioactive glove box. Thereafter, optimization studies were conducted to maximize decontamination efficiency and it was seen that oxygen in plasma plays a significant role. The same device was later scaled up to a multi-electrode model and used for similar radioactive waste removal. Both these devices under optimized condition could remove ∼92% radioactive wastes and the scaled up model reduced duration by 50%.

A single electrode microwave based atmospheric pressure plasma jet (APPJ) had been developed, characterized and applied for decontamination of Pu based synthetic radioactive waste. Argon plasma with small amount of CF4 and O2 was used for this purpose. The device was initially characterized by optical emission spectroscopy (OES) to determine its operational regime and used on Ta, a known surrogate of Pu for testing its efficacy in etching. Parametric optimization studies had been conducted thereafter on solid radioactive wastes of Pu and it was seen that presence of oxygen in plasma plays a crucial role in efficient removal of contamination. A scaled up multi-electrode version of this device was later designed and employed inside the glove box for similar studies. It was seen that 92 optimized condition with both the devices and the scaled up APPJ device reduced operation time by 50

BxC thin films were deposited on silicon (100) and sodalime glass substrates using Radio Frequency Plasma Enhanced Chemical Vapour Deposition (RF-PECVD) technique, at different substrate self-bias varying from -100V to -250V. Optical property, structure and stoichiometry of the films were determined by spectrophotometry, X-ray diffraction and proton elastic backscattering spectrometric measurements respectively to investigate the effect of film composition on microstructure and optical properties. Film refractive index at a typical wavelength of 400 nm increased from 1.87 to 1.97 on account of increasing packing density of the films with substrate self- bias. Decrease in direct and indirect optical band gap with increasing substrate self-bias, has been explained on the basis of compositional variation i.e. boron/carbon stoichiometric ratio. Finally, soft X-ray reflectivity in the wavelength range of 40 angstrom-360 angstrom has been measured to explore its potential for application as optical material in this region of electromagnetic spectrum.

Boron carbide films are increasingly being investigated for their application in new generation neutron detectors. It is implemented as conversion layer for neutrons and emerging as a potential alternative to He-3 based detectors. This work reports synthesis of boron carbide (BxC) films from ortho-carborane (o-C2B10H12) by radio frequency (RF) plasma enhanced chemical vapour deposition (PECVD) technique. Dependence of chemical composition, stoichiometry and total macroscopic cross section (Sigma(t)) has been studied as a function of self-bias on the substrate, varied in the range -75 V to -175 V. Films were characterized by 3D optical profilometry, X-ray photoelectron spectroscopy (XPS), proton elastic back scattering spectrometry (p-EBS), Fourier transform infra-red spectroscopy (FTIR) and Field Emission Scanning Electron Microscope (FESEM). Characterization results show noticeable change in the bulk as well as surface chemical composition, surface morphology and film stoichiometry with self-bias. Neutron transmission measurements exhibit increase in Sigma(t) from 170.47 cm(-1) for -75 V film to 273.38 cm(-1) for -175 V film with self-bias. (C) 2016 Elsevier B.V. All rights reserved.