In-Limbo: the In-Practice Islamic Banking System, in Full Conformity With Sharī ‘ah Standards Or.

In-Limbo; the In-practice Islamic Banking System, in full Conformity with Sharī ‘ah Standards or.

Modification in Structural, Optical and Electrical Properties of Polymer by Metal Ion Implantation

Ion implantation is an efficient technique to tailor physical and chemical properties by depositing a thin conductive layer in insulating polymers. For this purpose, Poly-Allyl-Diglycol-Carbonate (CR-39) is implanted by 400 keV Au+, Cu+ and Cr+ at normal incident angle with respect to target surface keeping the ion fluence in the range of 5×1013 ions/cm2 to 5×1015 ions/cm2 by employing a 400 kV NEC ion implanter. Simulation of ion implantation and damage processes generated in CR-39 is performed by using well-known software package named ‘Stopping and Range of Ions in Matter’ (SRIM). Modifications induced in structural, chemical, optical and electrical properties as well as surface morphology of metal ion-implanted CR-39 have been investigated as function of ion species and implantation fluence. Alterations in chemical and structural characteristics of CR-39 as a consequence of ion implantation are analyzed through Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy and X-ray diffraction (XRD). Optical response of polymeric material modified after ion implantation is explored by UV-Vis spectroscopy. DC electrical conductivity of ion-implanted specimens is determined by using four point probe technique. Atomic force microscope (AFM) is utilized for the analysis of surface features of implanted CR-39. It is revealed from SRIM/TRIM simulation that projected range and straggling of incorporated ion in CR-39 have increased for low atomic number of dopant ion. Both electronic and nuclear stopping of ions play vital role in energy transfer mechanism to target polymer. Their ratio depends on the nature of implanted ions and influences the damages induced in implanted material. Implantation-induced damages in the polymer increase with the rise in ion fluence. The depth distribution of implanted ions is Gaussian in shape for the selected range of ion fluence leading to maximum defect density at depths near the projected range of ions. Results, obtained from chemical and structural analyses, depict that both nature and implantation fluence of metal ions have synergistic impact on degradation of polymer matrix. Cr+ ion has induced more chemical alterations in implanted CR- 39, in comparison to Cu+ and Au+ ions, due to its greater projected range and Se/Sn ˃ 1, as estimated by SRIM. For lower ion fluences, the governing phenomenon in the structure of CR-39 is chain scission whereas, rate of cross-linking is increased at the expense of scission yield for higher ion fluences. The threshold fluence at which cross-linking is prominent is found to be 1×1014 ions/cm2 for Au+ and Cu+ ions whereas, the value for Cr+ ions is 5×1014 ions/cm2. Growth of sp2 carbonaceous clusters and transformation of Au+, Cu+ and Cr+-implanted CR-39 into amorphous carbon is evidenced for ion fluences ≥ 5×1014 ions/cm2. It is explored from UV-Vis spectra of implanted CR-39 that optical absorption is enhanced with red shift of absorption edge by increasing the ion fluence. It is attributed to ion implantation-induced defects in implanted polymer. Unsaturated carbon-rich clusters also exhibit strong correlation with fluence of three metal ions which serve as non-radiative centers and are responsible for color transformation of implanted specimens. Urbach energy of ion implanted CR-39 is raised with the increase in ion fluence. Urbach energy exhibits sigmoidal trend for Au+-implanted polymer whereas, it follows exponential function for Cu+- and Cr+-implanted CR-39. Direct and indirect band gap of implanted polymer have reduced with the rise in ion fluence. However, direct band gap is found wider than indirect band gap for a given ion fluence. Interestingly, optical response of CR-39 follows two-step behavior with threshold fluence of 1×1014 ions/cm2 for Au+- and Cu+-ion implantation and 5×1014 ions/cm2 for Cr+-ion implantation. This novel behavior is in good agreement with chemical properties of CR-39 implanted by three metal ions. Electrical conductivity of CR-39 is significantly enhanced from insulating to semi-conducting range upon implantation of selected metal ions. The electrical conductivity of polymer has increased with increase in ion fluence in non-linear fashion. It varies exponentially with fluence of implanted Au+ ions whereas, electrical conductivity of Cu+- and Cr+-implanted CR-39 represents sigmoidal curve, following Boltzmann function. The increasing trend of electrical conductivity of implanted CR- 39 with ion fluence is well correlated with reduction in optical band gap. Formation of surface nanostructures such as bulges, bumps, trenches, nano hillocks and nano craters is evidenced in implanted CR-39 by AFM analyses. These nanostructures are responsible for variation in surface roughness of CR-39 as function of fluence. Implantation of CR-39 by 400 keV Au+, Cu+ and Cr+ ions at relatively low ion fluences (5×1013 ions/cm2-5×1015 ions/cm2) resulted in modification in its structural, optical and electrical properties. Processing time of ion implantation can be effectively shortened at such low ion fluences in order to make CR-39 more economical and promising material for its potential applications in differrent fields. CR-39 with improved optical properties can be successfully employed for fabrication of optical sensors, diffractive structures, optical waveguides, optical displays, integrated optical circuits etc. Introduction of shallow conductive layer over insulating matrix opens gateway for CR-39 in soft electronics, organic electronics and microelectronics for fabrication of strain gauges, electrical bio-sensors, interconnects, micro-switches, frames for sensitive measuring devices etc.