Antibacterial and physicochemical properties of co‐sputtered CuSn thin films

Abstract

Copper-tin thin films (CT TFs) were deposited on p-type Si(100) by radio frequency (RF) magnetron co-sputtering method. The atomic ratio of Cu and Sn showed complementary tendency with various RF powers on metal targets. Antibacterial test was conducted with Gram-negative Escherichia coli. The ratio of Cu and Sn ions and the contact time with E. coli affected the antibacterial efficiency. Increasing the ratio of Cu ions and contact time showed higher antibacterial activity. Cu 20 Sn 6 called as bronze structure, metallic Cu, and copper oxide phases were identified from X-ray diffraction data after sterilization. The lattice strain that was changed due to the substitution of Cu and Sn was also calculated. The surface morphology of CT TFs was entirely grown to round shape when the dominant element was Sn. But, as the content of Cu increased, the surface morphology was changed from ball shape to sharp column shape. When fixed contact time, the intensities of Cu 2p increased but the intensities of Sn 3d decreased as increasing the atomic ratio of Cu. The oxidation of Cu was more sharply progressed as the RF power on Cu target increased. When fixed CT TFs, the intensities of Cu 2p were consistent but the intensities of Sn 3d 3/2 decreased as increasing contact time between CT TF and E. coli.

Antibacterial activity and mechanism of the silver nanoparticle in gram positive and negative bacteria

“…So increasing in thickness and roughness lead to increase in activity against bacteria [17]. This result agrees with previous researches [15,16]. Also we can see higher effective on Gram negative (Escherichia coli) than Gram positive bacteria (staphylococcus aureus).…”

“…Results show that films deposited with highest pressure has the highest antimicrobial activity this may be attributed to increase the thickness of coating layer and roughness which measure in AFM instrument. When thickness increase the amount of released Ag ions increase [15,16]. On the other hand increasing in roughness lead to greater interfacial contact between bacteria and surface of coating layer.…”

“…5. This because the energy can strongly change due to change of the working pressure, and we believe that the crucial parameter is the total energy delivered to the Ag films during its growth [15,16]. At an increase pressure the number of atom and molecules are increase; thus, the mean free path decreased and the collision rate of electrons with atoms is increased therefore instead of gaining energy by the electron from the electric field, more and more energy is transferred from electron to plasma species during inelastic collision, and the collision rate of electrons with atom and chamber wall is increase, thus the acquired energy of electron reduces, therefore the electron density increase [12,14].…”

Tailoring the Surface Characteristics of CuSe Thin Films by Adjusting the Compositional Ratio

“…[ 14,21,22 ] Cu 2+ has 3 d 9 structure while Cu + and Cu 0 have fully filled d ‐orbitals, 3 d 10 . [ 23,24 ] Therefore, Cu + and Cu 0 could not be distinguished due to the final state effect caused by the same number of electrons in the final subshell. [ 25,26 ] This is the basis for why we proceeded to deconvolute Cu + and Cu 0 as one peak in the Cu 2 p 3/2 peak.…”

Investigation of physicochemical properties of CuSn‐based PAN nanofibers prepared via electrospinning method

“…The doublet Sn 3d 5/2 XPS spectra are shown in Figure C,D for Sn and CuSn NFs, respectively. The Sn 3d 5/2 XPS spectra were deconvoluted into three peaks for metallic Sn (Sn 0 ) at 484.86 ± 0.1 eV, SnO 2 (Sn 4+ ) at 486.62 ± 0.1 eV, and Sn bond with C (denoted as Sn―C) peak at 483.7 ± 0.1 eV . The metal bond with carbon peaks, denoted as Cu―C and denoted as Sn―C, appeared at the low binding energy region.…”