Photonic crystals in biology

More documents

Recommendations

Info

Poster Session, Tuesday, June 15 Theme A1 - B702 Hollow Cathode Type Glow Discharge for Starch Modification Ritchie Eanes* and Sümeyra Bayır Department of Chemistry, Izmir Institute of Technology, Izmir 35430, Turkey Abstract— A home-built hollow cathode type dc glow discharge instrument modified with a special glass holder is used to effect possible surface and bulk modification of starch films. Specifically built for the study of the cross-linking of starch by plasma treatment, this device makes use of a hollow cathode arrangement towards enhanced plasma interactions. There is much interest in biodegradable polymers and in this regard much work has focused on the cross-linking of starch [see 1 and the references therein]. Although probably more often considered as a part of food science, starch, in its crosslinked or modified form, has found uses in non-food applications including those in the biomedical, pharmaceutical, and wastewater fields as mentioned by Ayoub and Rizvi in their review [2]. There are several methods available for the modification of starch; however, some of these methods require the use of rather exotic or potentially harmful crosslinking reagents [see 3 and references therein]. Zou et al. have described their modification of starch using a glow discharge plasma [3]. In their design, a starch slurry sample was placed in the positive column of their glow discharge device, between the anode and cathode. They concluded that a highly crosslinked starch could be obtained by using the glow discharge plasma in place of a more traditional chemical crosslinking reagent [3]. More recently, Bastos et al. have described the production of hydrophobic starch films by plasma treatment where the sample was placed directly on the cathode of a radio-frequency (rf) glow discharge apparatus [4]. The glow discharge is a useful medium for sputterdeposition [5] as well as analytical spectroscopies [6]. Under vacuum, gas is introduced into the region between an anode and cathode. This gas can be of the relatively "non-reactive" or "reactive" variety. Quite often argon, helium, or a combination of these two gases is used, especially for analytical glow discharge applications. More traditionally, both the anode and cathode are flat. However, especially for analytical glow discharge spectroscopy, the hollow-cathode design has gained interest due to the increased electron density of this electrode geometry. Also present in the plasma are ions of the discharge gas as well as the cathode. However, depending on the cathode material, the degree of sputtering of the cathode can be kept to a minimum [6]. In our dc glow discharge configuration, the cathode is large enough to contain a small sample that is immersed in the plasma by means of a glass L-shaped holder. By using holders of varying lengths, the sample can be placed at different positions within the glow discharge. Likewise, the cathode is attached to a probe that also allows adjustment in the position of the hollow cathode. This movable probe design is a modified form of the pin-type analytical glow discharge direct insertion probe of Duckworth and Marcus [7]. Other adjustable parameters include discharge voltage, discharge gas type, and pressure. By modifying these parameters, the shape and contents of the plasma can be varied as well as their degree of interaction with the sample. This work was partially supported by IYTE BAP project 2003 IYTE 02. N.R.E. is gratefully acknowledged for financial support. We thank Polat Bulanık for his glass blowing expertise and Prof. Dr. Tamerkan Özgen for the high voltage power supply and vacuum pump. Figure 1. Simple schematic of the hollow cathode glow discharge arrangement with the glass L-shaped sample holder immersed in the plasma. Figure 2. View through the UV transparent window of the inside of the hollow cathode glow discharge in operation without the glass sample holder in place. *Corresponding author: ritchieeanes@iyte.edu.tr [1] N. Reddy and Y. Yang. Food Chemistry. 118, 702-711 (2010). [2] A. S. Ayoub and S.S.H. Rizvi. J. Plastic Film & Sheeting. 25, 25-45 (2009). [3] J.-J. Zou, C-J. Liu, and B. Eliasson. Carbohydrate Polymers. 55, 23-26 (2004). [4] D.C. Bastos, A.E.F. Santos, M.L.V.J. da Silva, and R.A. Simão. Ultramicroscopy. 109, 1089-1093 (2009). [5] B. Chapman. Glow Discharge Processes. John Wiley & Sons, New York: 1980. [6] R. K. Marcus and J.A.C. Broekaert, Eds. Glow Discharge Plasmas in Analytical Spectroscopy. John Wiley & Sons, Chichester: 2003. [7] R. K. Marcus, Ed. Glow Discharge Spectroscopies. Plenum Press, New York: 1993, p. 309. 6th Nanoscience and Nanotechnology Conference, zmir, 2010 413
P P Mustafa Poster Session, Tuesday, June 15 Theme A1 - B702 Deposition and Characterization of ZnS Thin Films by Thermionic Vacuum Arc (TVA) Technique 1 1 1 1 1 UMehmet OzkanUP P* Naci EkemP Zafer BalbagP P, Suat PatP P, Sadan KorkmazP 1 PDepartment of Physics, Eskisehir Osmangazi University,Eskisehir 26480, Turkey Abstract-ZnS thin films have been deposited on a glass slide as substrate by thermionic vacuum arc technique from 3-6mm pieces of ZnS slugs. The deposited ZnS thin films were characterized for determining of the structural, morphological, and optical properties. Thickness and transparency of ZnS thin films were measured using optical method. Refractive index and band gap energies were calculated by Swanepoel method. AFM, SEM images and EDS analyses were realized to determine for surface morphology of produced ZnS thin films. According to obtained data deposited of ZnS thin film are in high purity and nano scaled. Band gap of the deposited ZnS thin films is approximately 3.7 eV ZnS is an important II–VI compound semiconductors with a large band gap of 3.67 eV in bulk material. It is used as a key material for light-emitting diodes, cathode-ray tubes, thin film electroluminescence, and window layers in photovoltaic cells. Semiconductor nanocrystals have received much attention in recent years because of their potential for use in fabrication of optoelectronic devices [1,2]. Preparations of thin films of these compounds are most often uses vacuum evaporation, chemical vapor deposition, sputtering, spray pyrolysis method and molecular beam epitaxy. Additionally, chemical bath deposition and photochemical are using the deposits ZnS thin film. [3, 4]. However, TVA was used firstly in ZnS thin film deposition. Thermionic vacuum arc (TVA) is a new technology for thin film deposition [5-8]. This technology has been supplied great advantages to deposited thin films like compact, low roughness, nanostructures, homogeneities, adhesive, high deposition rate etc [6]. A lot of materials were used for thin films production and characterization in this technique. TVA technique is gives ability to deposited pure thin films and alloys thin films. One of the biggest applications of TVA is thin films of high melting point materials like C, W, Mo, Nb, Ta, Re, B etc. Also, TVA cans ability to growth semiconductor thin films for photo voltaic applications and optoelectronic materials devices. Additionally, pure compounds thin films (two and more atoms) are enable for this technology like AlOR3R, ZnO, ZnTe, ZnS, SiOR2R, ZrOR2R etc from our research group [7]. Figure 1. Drawing of the TVA vacuum chamber and electrodes arrangements Thermionic vacuum arc materials plasma can be ignited in high or ultra high vacuum conditions between a heated cathode (special design for produced focused electron beam) and anode materials. Anode materials are consisting of the crucible and deposited materials. Due to the electron bombardment of the anode by the accelerated (with high voltage) and focused thermo-electrodes from the electron gun, the anode materials first melts and afterwards starts to evaporates in the inter electrodic space in vacuum chamber. Table 1. EDS analysis results for deposited ZnS thin films Elt. Line Intensity (c/s) Error 2-sig Conc Units O Ka 21.33 2.920 2.769 wt.% Si Ka 533.14 14.602 15.837 wt.% S Ka 1,282.63 22.648 34.931 wt.% Zn Ka 487.83 13.967 46.463 wt.% 100.000 wt.% Total Optical properties of deposited ZnS thin films are good harmony in literatures. A transmittance spectrum of deposited ZnS thin film is proper for Swanepoel method. Calculated refractive index value is 2.2. Band gap energy of it is approximately 3.7 eV. These results are also good harmony in literature and supported our results. Other measurement and analyses techniques show that surface of the deposited thin films are smooth, low roughness, compact. Additionally impurities of the structures were very small (4%). This impurities data were collect from glass slides. Because of deposited layer was 300 nm. *Corresponding author: mozkan@ogu.edu.tr [1] P. Roy, J. R. Ota, S. K. Srivastava, Thin Solid Films, 515 (2006) 1912-1917 [2] H. J. Lee, S. I. Lee, Current Applied Physics 7 (2007) 193-197 [3] M. Innocenti, G. Pezzatini, F. Forni, M.L. Foresti, J. Electrochem. Soc. 148 (2001) C357. [4] J. H. Fendler, Nanoparticles and Nanostructured Films, Wiley- VCH, Weinheim. 1998 [5] N. Ekem, G. Musa, S.Pat, Z.Balbag, I. Cenik , R. Vladoiu, J. Opt. and Adv. Mater, Vol. 10, No. 3, March 2008, p. 672 – 674 [6] C.Surdu-Bob, I.Mustata, C.Iacob, Journal of Optoelectronics and Advanced Materials, Vol9 No9,2007,2932-2934 [7] G.Musa, I.Mustata, V.Ciupina, R.Vladoiu, G.Prodan, E.Vasile, H.Ehrich , Diamond and Related Materials 13 (2004) 1398–1401 [8] HBalbag MZH, HPat SH, HCenik MIH. , HAkan TH, HEkem NH, HMusa GH, Journal of Optoelectronics and Advanced Materials, Vol. 9 No: 4, 2007,p. Pages: 858-861 6th Nanoscience and Nanotechnology Conference, zmir, 2010 414
Page 1 and 2:
Poster Presentations 1st Day 2nd Da
Page 3 and 4:
Poster Session, Tuesday, June 15 Th
Page 5 and 6:
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Page 57 and 58:
Page 59 and 60:
Page 61 and 62:
Page 63 and 64:
Page 65 and 66:
Page 67 and 68:
Poster Session, Tuesday, June 15 Sy
Page 69 and 70:
Page 71 and 72:
Page 73 and 74:
P Poster Session, Tuesday, June 15
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
P P P,P Poster Session, Tuesday, Ju
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
P P P and Poster Session, Tuesday,
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Poster Session, Tuesday, June 15 Hy
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156: Poster Session, Tuesday, June 15 Th
Page 173 and 174: Poster Session, Tuesday, June 15 Pr
Page 201 and 202: P Torr. pressure P pressure P and P
Page 205: Poster Session, Tuesday, June 15 Th
show all

Photonic crystals in biology

Create successful ePaper yourself

Delete template?

Save as template?