Fortunato, E.a, Assunção Gonçalves Marques Águas Pereira Ferreira Vilarinho Martins V. a A. a. "
High quality conductive gallium-doped zinc oxide films deposited at room temperature."
Thin Solid Films. 451-452 (2004): 443-447.
AbstractTransparent and highly conducting gallium-doped zinc oxide films were successfully deposited by rf sputtering at room temperature. The lowest resistivity achieved was 2.6×10-4 Ω cm for a thickness of 1100 nm (sheet resistance ≈1.6 Ω/sq), with a Hall mobility of 18 cm2/Vs and a carrier concentration of 1.3×1021 cm-3. The films are polycrystalline with a hexagonal structure and a strongly preferred orientation along the c-axis. A linear dependence between the mobility and the crystallite size was obtained. The films present a transmittance in the visible spectra between 80 and 90% and a refractive index of approximately 2, which is very close to the value reported for bulk material. © 2003 Elsevier B.V. All rights reserved.
Fortunato, E., Nunes Marques Costa Águas Ferreira Costa Martins P. A. D. "
Highly conductive/transparent ZnO:Al thin films deposited at room temperature by rf magnetron sputtering."
Key Engineering Materials. 230-232 (2002): 571-574.
AbstractTransparent conducting ZnO:Al thin films have been deposited on polyester (Mylar type D, 100 μm thickness) substrates at room temperature by r.f. magnetron sputtering. The structural, optical and electrical properties of the deposited films have been studied. The samples are polycrystalline with a hexagonal wurtzite structure and a strong crystallographic c-axis orientation (002) perpendicular to the substrate surface. As deposited ZnO:Al thin films have an 85% transmittance in the visible and infra-red region and a resistivity as low as 3.6×10-2 Ωcm. The obtained results are comparable to those ones obtained on glass substrates, opening a new field for low cost, light weight, small volume, flexible and unbreakable large area optoelectronic devices.
Martins, R., Ferreira Cabrita Fortunato I. A. E. "
Improvement of a-Si:H device stability and performances by proper design of the interfaces."
Journal of Non-Crystalline Solids. 266-269 B (2000): 1094-1098.
AbstractThis paper deals with a new design method for the interfaces of a-Si:H pin solar cells that improves the stability and performances of devices deposited in a single batch chamber process. The method consists in removing a deposited sacrificial layer placed between the p/i and/or i/n interfaces by etching. This layer is an absorber of defects and impurities that are introduced in the interfaces, mainly from the chamber walls cross-contamination and the substrate surface. The results achieved increase the device fill factor and short circuit current density, respectively towards 75% and 16.3 mA cm-2, with a final efficiency of about 10%, before light soaking experiments. © 2000 Elsevier Science B.V. All rights reserved.