Cohesive strength of nanocrystalline ZnO:Ga thin films deposited at room temperature

In this study, transparent conducting nanocrystalline ZnO:Ga (GZO) films were deposited by dc magnetron sputtering at room temperature on polymers (and glass for comparison). Electrical resistivities of 8.8 × 10-4 and 2.2 × 10-3 Ω cm were obtained for films deposited on glass and polymers, respectively. The crack onset strain (COS) and the cohesive strength of the coatings were investigated by means of tensile testing. The COS is similar for different GZO coatings and occurs for nominal strains approx. 1%. The cohesive strength of coatings, which was evaluated from the initial part of the crack density evolution, was found to be between 1.3 and 1.4 GPa. For these calculations, a Young's modulus of 112 GPa was used, evaluated by nanoindentation

Flexible CuInSe2 photovoltaic cells fabricated by non-vacuum techniques

In this work, CuInSe 2 based flexible photovoltaic cells have been fabricated completely using non-vacuum low-cost techniques. Thin films were deposited on molybdenum thin foil substrates by electrodeposition using a buffered aqueous electrolyte with the deposition of subsequent layers performed by spray pyrolysis. In addition, the buffer layer CdS was replaced with a wider bandgap ZnS (3.7 eV) and analysis undertaken of the fabrication pathway, morphological and compositional changes resulting from the different precursor route. The deposited films were annealed in a Se atmosphere at 450 °C. The influence of annealing temperature and time on the properties of the films are briefly discussed. Characterisation of thin films was performed using aqueous electrolyte contacts. Capacitance measurements were made as a function of applied bias on thin films deposited on metal substrates with blocking electrolyte contacts where analysis of the impedance gave values of the space charge capacitance from which the doping density and flat band potential were derived. The structural characterisation was carried out using X-ray diffraction and Raman spectroscopy. The structure and device properties of Mo (SS)/CuInSe 2/ZnS/n +-ZnO/Ni were characterized using current-voltage technique and photocurrent spectroscopy. © 2011 Elsevier B.V.This work was supported by the Spanish Government through MEC grant MAT2009-14625-C03-03 and the Fundacao para a Ciencia e a Tecnologia (FCT) in Portugal.Samantilleke, AP.; Sahal, M.; Ortiz Moya, L.; Cerqueira, M.; Marí Soucase, B. (2011). Flexible CuInSe2 photovoltaic cells fabricated by non-vacuum techniques. Thin Solid Films. 519:7272-7275. https://doi.org/10.1016/j.tsf.2011.01.373S7272727551

p-type behavior of electrodeposited ZnO:Cu thin films

Cu-doped ZnO (ZnO:Cu) thin films and ZnO/ ZnO:Cu homojunction devices were electrodeposited on conductive glass substrates in a non-aqueous electrolyte containing Cu and Zn salts. The Cu content of the films is proportional to the Cu/Zn precursor ratio in the deposition electrolyte. ZnO:Cu was found to be of a hexagonal wurtzite structure with (002) preferred orientation. A transition from n-type to p-type was observed for ZnO:Cu films with a Cu/ Zn ratio higher than 2% as inferred from the change in the direction of the photocurrent. The rectifying characteristics shown by homojunction devices further confirm the p-type conductivity of ZnO:Cu layers.This work was supported by the Spanish Government through MEC grant MAT2009-14625-C03-03 and the Portuguese Foundation for Science and Technology (FCT), CIENCIA 2007. Financial support by the European Commission through NanoCIS project (PIRSESGA-2010-269279) is gratefully acknowledged.Marí Soucase, B.; Sahal, M.; Mollar García, MA.; Cerqueira, F.; Samantilleke, AP. (2012). p-type behavior of electrodeposited ZnO:Cu thin films. Journal of Solid State Electrochemistry. 16(1):1-5. https://doi.org/10.1007/s10008-011-1635-xS15161Klingshirn C (2007) Phys Status Solidi B 244:3027–3073Lyons JL, Janotti A, Van de Walle CG (2009) Appl Phys Lett 95:252105–252107Zunger A (2008) Appl Phys Lett 83:1830–1832Park CH, Zhang SB, Wie S (2002) Phys Rev B 66:073202–073204Yan Y, Al-Jassim MM, Wie S (2006) Appl Phys Lett 89:181912–181914Park MS, Min BI (2003) Phys Rev B 68:224436–224441Shukla G (2009) Appl Phys A 97:115–118Buchholz DB, Chang RPH, Song JH, Ketterson JB (2005) Appl Phys Lett 87:82504–82506Rahmani MB, Keshmiri SH, Shafiei M, Latham K, Wlodarski W, du Plessis J, Kalantar-Zadeh K (2009) Sensor Letters 7:621–628Lincot D (2005) Thin Solid Films 487:40–48Tortosa M, Mollar M, Marí B (2007) J Crystal Growth 304:97–102Tortosa M, Mollar M, Marí B, Lloret F (2008) J Appl Phys 104:033910–033914Mollar M, Tortosa M, Casasús R, Marí B (2009) Microelectronics J 40:276–279Marí B, Elmanouni A, Damonte L, Mollar M (2010) Phys Status Solidi A 207:1623–1626Cembrero J, Busquets-Mataix D (2008) Thin Solid Films 517:2859–2864Marí B, Cembrero J, Mollar M, Tortosa M (2008) Phys Status Solidi C 5:555–558Fisicaro P, Adriaens A, Ferrara E, Prenesti E (2007) Anal Chim Acta 597:75–81Manjón FJ, Marí B, Serrano BJ, Romero AH (2005) J Appl Phys 97:053516–053519Rajeshawar K (2001) Fundamentals of semiconductor electrochemistry and photoelectrochemistry. In: Licht S (ed) Encyclopedia of electrochemistry. Wiley-VCH, Weinheim, pp 38–39Zoski CG (2007) Handbook of electrochemistry. Elsevier, Amsterdam, pp 336–35

Synthesis of Sr(1-x-y)Al4O7:Eux2+, Lny3+ (Ln= Dy, Y, Pr) Nanophosphors Using Rapid Gel Combustion Process and Their Down Conversion Characteristics

[EN] Eu2+ and Eu2++Ln3+ doped SrAl4O7 nanophosphors were synthesized by rapid gel combustion process. The morphology of prepared phosphors was examined with scanning and transmission electron microscopy. The phase identification and the crystal structures of nanophosphors were studied using X-ray powder diffraction techniques. Luminescence characteristics of the prepared nanophosphors were analyzed on account of excitation, emission and phosphorescence decay analysis. The emission spectra demonstrated the broad green emission attributed to 4f65d1→ 4f7 transition of the Eu2+ ions. The effect of codoping of some trivalent lanthanide (Dy3+, Pr3+ and Y3+) ions were investigated for improving the emission intensity and phosphorescence decay time of the basic lattice of SrAl4O7:Eu2+ phosphors. The synthesized materials had enhanced bright luminescent properties that could suitably be applied for display as well as photovoltaic applications. Devender Singh, Vijeta Tanwar, Anura P. Samantilleke, Bernabe Mari, Shri Bhagwan, Krishan C. Singh, Pratap S. Kadyan, Ishwar SinghThe authors thankfully recognize the financial support from the University Grant Commission (UGC), New Delhi [MRP-40-73/2011(SR)] and the European Commission through Nano CIS project (FP7-PEOPLE-2010-IRSES ref. 269279).Singh, D.; Tanwar, V.; Samantilleke, AP.; Marí, B.; Bhagwan, S.; Singh, KC.; Kadyan, PS.... (2017). Synthesis of Sr(1-x-y)Al4O7:Eux2+, Lny3+ (Ln= Dy, Y, Pr) Nanophosphors Using Rapid Gel Combustion Process and Their Down Conversion Characteristics. Electronic Materials Letters. 13(3):222-229. doi:10.1007/s13391-017-6038-4S222229133B. Zhang, C. Zhao, and D. Chen, J. Bio. Chem. Lumin. 25, 25 (2010).A. Nag and T. R. N. Kutty, J. Alloys Compd. 354, 221 (2003).S. H. Choi, N. H. Kim, Y. H. Yun, and S. C. Choi, J. Ceram. Process. Res. 7, 62 (2006).B. M. Smets, Mater. Chem. Phys. 16, 283 (1987).C. R. Ronda, J. Lumin. 72-74, 49 (1997).V. Chernov, T. M. Piters, R. Melendrez, W. M. Yen, E. 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