Customer Papers
This is a searchable database of papers written by our customers, using Cambridge NanoTech systems. If you are publishing a paper based on research done on a Cambridge NanoTech ALD system, please contact us. We would be pleased to include it in our database.Showing customer papers 1-10 of 82 Next
| LINK | Pitzschel, K.; Moreno, J. M. M.; Escrig, J.; Albrecht, O.; Nielsch, K.; Bachmann, J. |
| "Controlled Introduction of Diameter Modulations in Arrayed Magnetic Iron Oxide Nanotubes" | |
| ACS Nano, 2009, 3, 3463-3468 | |
| Abstract: | To date, no large-scale preparative method for arrays of nanotube enables the experimentalist to arbitrarily define changes in the tubes\' diameter along their length. To this goal, we start with anodic alumina substrates displaying controlled modulations in pore diameter obtained by alternating \"mild\" and \"hard\" electrochemical etching conditions. We then utilize atomic layer deposition (ALD) to coat the internal pore walls with conformal layers of an oxide. Ferromagnetic Fe3O4 tubes of 10 nm wall thickness and 10-30 mu m in length are thus prepared, which replicate the modulated silhouette of the template. Their magnetic properties strongly depend on the presence of diameter modulations. Introducing one or several very short segments of large diameter (150 nm) into an otherwise thin tube (70 nm diameter) brings its initially large coercive field down to a value close to the case of a homogeneously thick tube. Theoretical modeling emphasizes the major influence of the magnetostatic interactions between neighboring tubes. They are enhanced locally at the sites of diameter modulations, which directly translates into a reduction in coercive field. |
| Address: | Bachmann, J Univ Hamburg, Inst Appl Phys, Hamburg, Germany Univ Hamburg, Inst Appl Phys, Hamburg, Germany Univ Hamburg, Inst Appl Phys, Hamburg, Germany Univ Barcelona, Dept Quim Fis, Electrodep, E-08028 Barcelona, Spain Univ Santiago Chile, Dept Fis, Santiago, Chile |
| LINK | Shanmugam, M.; Baroughi, M. F.; Galipeau, D. |
| "Effect of atomic layer deposited ultra thin HfO2 and Al2O3 interfacial layers on the performance of dye sensitized solar cells" | |
| Thin Solid Films, 2010, 518, 2678-2682 | |
| Abstract: | The objective of this work was to investigate the improvement in performance of dye sensitized solar cells (DSSCs) by depositing ultra thin metal oxides (hafnium oxide (HfO2) and aluminum oxide (Al2O3)) on mesoporous TiO2 photoelectrode using atomic layer deposition (ALD) method. Different thicknesses of HfO2 and Al2O3 layers (5, 10 and 20 ALD cycles) were deposited on the mesoporous TiO2 surface prior to dye loading process used for fabrication of DSSCs. It was observed that the ALD deposition of ultrathin oxides significantly improved the performance of DSSCs and that the improvement in the DSSC performance depends on the thickness of the deposited HfO2 and Al2O3 films. Compared to a reference DSSC the incorporation of a HfO2 layer resulted in 69% improvement (from 4.2 to 7.1%) in the efficiency of the cell and incorporation of Al2O3 (20 cycles) resulted in 19% improvement (from 4.2 to 5.0%) in the efficiency of the cell. These results suggest that ultrathin metal oxide layers affect the density and the distribution of interface states at the TiO2/organic dye and TiO2/liquid electrolyte interfaces and hence can be utilized to treat these interfaces in DSSCs. (C) 2009 Elsevier B.V. All rights reserved. |
| Address: | Baroughi, MF S Dakota State Univ, Dept Elect Engn |
| LINK | Alessandri, I.; Zucca, M.; Ferroni, M.; Bontempi, E.; Depero, L. E. |
| "Tailoring the Pore Size and Architecture of CeO2/TiO2 Core/Shell Inverse Opals by Atomic Layer Deposition" | |
| Small, 2009, 5, 336-340 | |
| Abstract: | |
| Address: | Alessandri, I Univ Brescia, INSTM, Via Branze 38, I-25123 Brescia, Italy Univ Brescia, INSTM, Via Branze 38, I-25123 Brescia, Italy Univ Brescia, INSTM, I-25123 Brescia, Italy Univ Brescia, Chem Technol Lab, I-25123 Brescia, Italy Univ Brescia, CNR INFM, I-25123 Brescia, Italy Univ Brescia, Dept Chem |
| LINK | Katsia, E.; Huby, N.; Tallarida, G.; Kutrzeba-Kotowska, B.; Perego, M.; Ferrari, S.; Krebs, F. C.; Guziewicz, E.; Godlewski, M.; Osinniy, V.; Luka, G. |
| "Poly(3-hexylthiophene)/ZnO hybrid pn junctions for microelectronics applications" | |
| Applied Physics Letters, 2009, 94, - | |
| Abstract: | Hybrid poly(3-hexylthiophene)/ZnO devices are investigated as rectifying heterojunctions for microelectronics applications. A low-temperature atomic layer deposition of ZnO on top of poly(3-hexylthiophene) allows the fabrication of diodes featuring a rectification ratio of nearly 10(5) at /- 4 V and a current density of 10(4) A/cm(2). Electrical characteristics are discussed taking into account the chemical structure of the stack and the energy band diagram. |
| Address: | Katsia, E CNR INFM, Lab Nazl MDM, Via Olivetti 2, I-20041 Agrate Brianza, Italy CNR INFM, Lab Nazl MDM, Via Olivetti 2, I-20041 Agrate Brianza, Italy CNR INFM, Lab Nazl MDM, I-20041 Agrate Brianza, Italy Tech Univ Denmark, Riso Natl Lab Sustainable Energy, DK-4000 Roskilde, Denmark Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland |
| LINK | Chang, C. Y.; Chou, C. T.; Lee, Y. J.; Chen, M. J.; Tsai, F. Y. |
| "Thin-film encapsulation of polymer-based bulk-heterojunction photovoltaic cells by atomic layer deposition" | |
| Organic Electronics, 2009, 10, 1300-1306 | |
| Abstract: | This study demonstrated thin-film encapsulation of bulk-heterojunction polymer photovoltaic cells. utilizing a process based on atomic layer deposition (ALD) that both prevented degradation caused by ambient gases and served as an annealing step that increased the initial efficiency of the cells. With the ALD temperature set at 140 degrees C and the total deposition time set at 1 h, the photovoltaic cells, based on blended poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C-61 butyric acid methylester (PCBM), were optimally annealed during achieving a power conversion efficiency (PCE) of 3.66%. Encapsulating the encapsulation, cells with a 26 nm Al2O3/HfO2 nanolaminated film overcoated with an epoxy resin protection layer enabled the cells to obtain an in-air degradation rate that was similar to cells that were stored in nominally O-2/H2O-free atmosphere. The nanolaminated structure of the encapsulation film resolved the issue of hydrolysis-induced aging observed with Al2O3 films, owing to the hydrophobicity of the HfO2 layers. Additionally. extended exposure of the ALD precursors during the ALD process significantly improved the coverage of the ALD films over the P3HT/PCBM active layer at the perimeter of the cells. (C) 2009 Elsevier B.V. All rights reserved. |
| Address: | Tsai, FY Natl Taiwan Univ, Dept Mat Sci |
| LINK | Chen, Z.; Sarkar, S.; Biswas, N.; Misra, V. |
| "Atomic Layer Deposition of Hafnium Dioxide on TiN and Self-Assembled Monolayer Molecular Film" | |
| Journal of The Electrochemical Society, 2009, 156, H561-H566 | |
| Abstract: | Hafnium dioxide (HfO2) thin films with thicknesses ranging from 20 to 100 have been grown in a viscous flow reactor using atomic layer deposition (ALD) with tetrakis(dimethylamido)hafnium(IV) and water as the reactants. HfO2 ALD films are deposited successfully at 200 degrees C on different molecular monolayers. X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy analyses show a continuous growth of the HfO2 layer on the self-assembled monolayer molecules. Electrical properties characterized by current-voltage measurements suggest that three parameters play important roles in determining the physical structure of HfO2, namely, the precursor pulse time, the sample exposure time, and the time for purging out an unreacted precursor. ALD conditions for different substrates have been optimized so that excellent electrical properties can be obtained for HfO2 films on molecules. Transmission electron microscopy of 30 and 60 ALD HfO2 on TiN and molecular monolayers shows a continuous deposition of HfO2. This process enables the development of a class of molecular electronic devices, solid-state molecular memory devices. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3125722] All rights reserved. |
| Address: | N Carolina State Univ, Dept Elect |
| LINK | Gorrn, P.; Riedl, T.; Kowalsky, W. |
| "Encapsulation of Zinc Tin Oxide Based Thin Film Transistors" | |
| Journal of Physical Chemistry C, 2009, 113, 11126-11130 | |
| Abstract: | In this paper, we study the effect of thin film encapsulation on transparent thin film transistors (TFTs) with zinc tin oxide channel layers deposited by oxygen plasma assisted pulsed laser deposition (PAPLD). Chemisorption and desorption of oxygen are identified as the most important physical processes governing the impact of surface passivation on the device characteristics. For an in-depth study, we apply three different methods to remove chemisorbed oxygen from the channel surface: thermally activated desorption in vacuum; light induced desorption; and chemical reaction with the highly reactive agent trimethyl aluminum (TMA) during atomic layer deposition (ALD) thin film encapsulation. In each case, the removal of chemisorbed oxygen significantly shifts the threshold voltage of the TFTs on the order of 1-2 V. On the basis of the understanding gained in these experiments, a two-step encapsulation process is proposed that enables the application of high-performance ALD grown permeation barriers layers without alteration of the device characteristics. This finding is an essential step toward active matrix OLED displays with metal oxide driving electronics. |
| Address: | Gorrn, P Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA Tech Univ Carolo Wilhelmina Braunschweig, Inst High Frequency Technol, D-38106 Braunschweig, Germany |
| LINK | Klahr, B. M.; Hamann, T. W. |
| "Performance Enhancement and Limitations of Cobalt Bipyridyl Redox Shuttles in Dye-Sensitized Solar Cells" | |
| Journal of Physical Chemistry C, 2009, 113, 14040-14045 | |
| Abstract: | A series of one-electron outersphere cobalt bipyridyl redox couples were used as redox shuttles in dyesensitized solar cells (DSSCs). Atomic layer deposition was used to deposit an ultrathin coating of alumina on nanoparticle-based TiO2 DSSC photoanodes, which results in significantly improved quantum yields for all of the DSSCs containing outersphere redox systems. However, a significant discrepancy in performance remains between DSSCs containing the different cobalt redox shuttles. Variation of the driving force for regeneration by similar to 500 mV, by employing [Ru(bpy)2(4,4\'-dicarboxy-bpy)](PF6)2 as a dye, combined with concentration dependence studies indicates that the cobalt redox couples are not limited by dye regeneration; however, in certain cases the iodide electrolyte was, one of the very few systems where alternate redox Couples perform significantly better than triiodide/iodide. Electron lifetimes were measured with the open circuit voltage decay technique, The differences in the lifetimes (recombination kinetics) of DSSCs employing cobalt redox couples correlate well with the differences in the incident photon-to-current efficiencies (IPCEs), providing strong evidence that the external quantum efficiencies of DSSCs with cobalt polypyridyl redox couples are limited by recombination. We further found that, contrary to previous reports, the cobalt(III/II) tris(4,4\'-diniethyl-2,2\'-bipyridine) couple can produce comparable external quantum yields to cobalt(III/II) tris(4,4\'-di-tert-butyl-2,2\'-bipyridine) when employed as redox shuttles in DSSCs. However, the photovoltaic performances of both are constrained by mass transport of the oxidized species through the nanoparticle photoelectrode. |
| Address: | Hamann, TW Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA Michigan State Univ, Dept Chem, E Lansing, MI 48824 USA |
| LINK | Lamagna, L.; Wiemer, C.; Baldovino, S.; Molle, A.; Perego, M.; Schamm-Chardon, S.; Coulon, P. E.; Fanciulli, M. |
| "Thermally induced permittivity enhancement in La-doped ZrO2 grown by atomic layer deposition on Ge(100)" | |
| Applied Physics Letters, 2009, 95, - | |
| Abstract: | La-doped ZrO2 thin films grown by O-3-based atomic layer deposition directly on Ge(100) exhibit a dielectric constant of 29. Upon annealing in N-2 at 400 degrees C, a high kappa value >40 is extracted for film thickness below 15 nm. Compositional depth profiling allows to correlate this observation with a remarkable Ge interdiffusion from the substrate which is consistent with the stabilization of the tetragonal ZrO2 phase. Ge interaction with the oxide stack and the formation of a germanate-like interfacial region, which acts as an electrical passivation for the Ge surface, are also investigated. (C) 2009 American Institute of Physics. [doi:10.1063/1.3227669] |
| Address: | Lamagna, L INFM, CNR, Lab Nazl MDM, Via C Olivetti 2, I-20041 Agrate Brianza, MI, Italy INFM, CNR, Lab Nazl MDM, Via C Olivetti 2, I-20041 Agrate Brianza, MI, Italy INFM, CNR, Lab Nazl MDM, I-20041 Agrate Brianza, MI, Italy CNRS, CEMES, F-31055 Toulouse 4, France Univ Toulouse, nMat Grp, F-31055 Toulouse 4, France Univ Milano Bicocca, Dipartimento Sci Mat, I-20126 Milan, Italy |
| LINK | Lee, B.; Choi, K. J.; Hande, A.; Kim, M. J.; Wallace, R. M.; Kim, J.; Senzaki, Y.; Shenai, D.; Li, H.; Rousseau, M.; Suydam, J. |
| "A novel thermally-stable zirconium amidinate ALD precursor for ZrO2 thin films" | |
| Microelectronic Engineering, 2009, 86, 272-276 | |
| Abstract: | ZrO2 thin films were deposited by the atomic layer deposition process on Si substrates using tetrakis(N,N\'-dimethylacetamidinate) zirconium (Zr-AMD) as a Zr precursor and H2O as an oxidizing agent. Tetrakis (ethylmethylamino) zirconium (TEMA-Zr) was also evaluated for a comparative study. Physical properties of ALD-derived ZrO2 thin films were studied using ellipsometry, grazing incidence XRD (Gl-XRD), high resolution TEM (HRTEM), and atomic force microscopy (AFM). The ZrO2 deposited using Zr-AMD showed a better thermal stability at high substrate temperature (>300 IQ compared to that using TEMA-Zr. GI-XRD analysis reveals that after 700 degrees C anneal both ZrO2 films enter tetragonal phase. The electrical properties of N-2-annealed ZrO2 film using Zr-AMD exhibit all EOT of 1.2 nm with leakage current density as low as 2 x 10(-3) A/cm(2) (@V-(sic)-1 V). The new Zr amidinate is a promising ALD precursor for high-k dielectric applications. (C) 2008 Elsevier B.V. All rights reserved. |
| Address: | Kim, J Univ Texas Dallas, Richardson, TX 75083 USA Univ Texas Dallas, Richardson, TX 75083 USA Univ Texas Dallas, Richardson, TX 75083 USA Rohm |
Showing customer papers 1-10 of 82 Next