Garcia Molina, Francisco Miguel
Total activity: 7
Research group
MNT - Micro and Nanotechnologies Research Group
Department
Department of Electronic Engineering
E-mail
mgmolinaeel.upc.edu
Contact details
UPC directory Open in new window

Graphic summary
  • Show / hide key
  • Information


Scientific and technological production
  •  

1 to 7 of 7 results
  • Optimization of laser processes for local rear contacting of passivated silicon solar cells

     Colina Brito, Monica Alejandra; Martin Garcia, Isidro; Voz Sanchez, Cristobal; Morales Vilches, Ana Belen; Ortega Villasclaras, Pablo Rafael; Lopez Rodriguez, Gema; Garcia Molina, Francisco Miguel; Alcubilla Gonzalez, Ramon
    Energy procedia
    Date of publication: 2014-01-31
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Laser Firing Contact (LFC) and Laser Doping (LD) have become potential alternatives to the Al BSF thermal processing conventionally used in p-type c-Si solar cell rear contacts. Optimized LFC and LD processes allow, not only the generation of efficient micro-contacts, but also the diffusion of p-type doping impurities reducing the surface recombination velocity due to the formation of a local back surface field (BSF). In this work, three different laser strategies to create ohmic micro-contacts are studied: 1) evaporated Aluminum LFC, 2) Aluminum foil LFC and 3) Aluminum oxide (Al2O3) LD. The laser source used was a pulsed Nd-YAG 1064 nm laser working in the nanosecond regime. Laser parameters were explored to optimize the electrical behavior of the contacts and their carrier recombination rate. Optimized laser parameters lead to specific contact resistance in the 1.0 1.3 m¿¿cm2 range for all three strategies. From the point of view of carrier recombination, better results were obtained for Al2O3 LD, probably related to the lower energy pulse needed to create the contact. Next, the three proposed laser approaches were applied to the back surface of heterojunction silicon solar cells. Contact quality was not limiting any cell performance indicating that the contact quality is good enough to be applied in high-efficiency c-Si cell concepts. On the other hand, surface recombination velocity at the rear surface on the final devices also points out to Al2O3 LD as the best alternative.

  • Boron diffused emitters passivated with Al2O3 films

     Masmitja Rusinyol, Gerard; Ortega Villasclaras, Pablo Rafael; Lopez Rodriguez, Gema; Calle Martin, Eric; Garcia Molina, Francisco Miguel; Martin Garcia, Isidro; Orpella Garcia, Alberto; Voz Sanchez, Cristobal; Alcubilla Gonzalez, Ramon
    Spanish Conference on Electron Devices
    Presentation's date: 2013
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this work we study the fabrication and characterization of boron diffused emitters using FZ c-Si(n) substrates. Emitter surface was passivated with Al2O3(25 nm thick) layers deposited by thermal atomic layer deposition ALD technique. This study covers a broad emitter sheet resistance Rsh range from 20 to 250 O/sq using both polished and textured wafers. Emitter electrical quality was tested by means of lifetime measurements using quasi-stationary photoconductance QSS-PC method. Dark saturation emitter current densities Joe's were extracted from lifetime measurements resulting in Joe's values ranging from 10 to 150 fA/cm2 depending on Rsh. These results are in the-state-of-the-art in boron emitter passivation.

    In this work we study the fabrication and characterization of boron diffused emitters using FZ c-Si(n) substrates. Emitter surface was passivated with Al2O3(25 nm thick) layers deposited by thermal atomic layer deposition ALD technique. This study covers a broad emitter sheet resistance Rsh range from 20 to 250 Ω/sq using both polished and textured wafers. Emitter electrical quality was tested by means of lifetime measurements using quasi-stationary photoconductance QSS-PC method. Dark saturation emitter current densities Joe's were extracted from lifetime measurements resulting in Joe's values ranging from 10 to 150 fA/cm2 depending on Rsh. These results are in the-state-of-the-art in boron emitter passivation.

  • Hypobaric chamber for wind sensor testing in Martian condictions

     Kowalski, Lukasz; Garcia Molina, Francisco Miguel
    Spanish Conference on Electron Devices
    Presentation's date: 2011-02-08
    Presentation of work at congresses

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    In this paper we will describe the installation of a low pressure stainless steel horizontal chamber to be used in preliminary tests of a Mars atmosphere wind sensor. It includes custom made additional QF ports, electric and pneumatic interfaces together with a vacuum pump system. Absolute pressure, as a function of the pump operational time during the vacuum process and depressurization will be shown as a result of experimental measurements. We will propose the integration of a typical compact wind tunnel with interior of the vacuum chamber. We will also discuss the possibility of the reproduction the same Reynolds number conditions for a given low temperature of a pure carbon dioxide atmosphere just by fine adjustment of either air pressure or air velocity inside the chamber at typical laboratory temperature. Finally, we will recapitulate all pros and cons of this hypobaric chamber.

  • Células fotovoltaicas con un rendimiento del 20.5%

     Ortega Villasclaras, Pablo Rafael; Lopez Rodriguez, Gema; Orpella Garcia, Alberto; Martin Garcia, Isidro; Colina Brito, Monica Alejandra; Voz Sanchez, Cristobal; Bermejo Broto, Alexandra; Puigdollers Gonzalez, Joaquin; Garcia Molina, Francisco Miguel; Alcubilla Gonzalez, Ramon
    Solar News
    Date of publication: 2011-03-01
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Un grupo de investigadores de la Universitat Politècnica de Catalunya (UPC) han desarrollado un proceso de fabricación que permite obtener rendimientos de conversión fotovoltaicos del 20,5%. Esto supone una mejora sustancial con respecto a los rendimientos habituales en células comerciales que sitúa en un 15%, y la cuota más elevada a la que se ha llegado hasta ahora en España. En estos momentos trabajan en mejoras que las hagan accesibles industrialmente. El avance, tras años de investigación, consiste en minimizar los diferentes mecanismos de pérdidas que influyen en el cómputo de la eficiencia de conversión fotovoltaica.

  • 3D metallo-dielectric structures combining electrochemical and electroplating techniques

     Hernández, D.; Lange, Diego; Todorov Trifonov, Trifon; Garin Escriva, Moises; Garcia Molina, Francisco Miguel; Rodriguez Martinez, Angel; Alcubilla Gonzalez, Ramon
    Microelectronic engineering
    Date of publication: 2010-06
    Journal article

    Read the abstract Read the abstract View View Open in new window  Share Reference managers Reference managers Open in new window

    Three-dimensional (3D) periodic nickel micro-structures with a periodicity of 4 μm and high number of structural periods were fabricated by electrodeposition. Macroporous silicon, consisting of periodic arrays of sine-wave modulated pores, was used as a deposition template. It was prepared by electrochemical etching of silicon and subsequent pore widening by multiple oxidation/oxide-removal steps. The pore widening allows to open windows between adjacent pores obtaining a 3D network of interconnected voids embedded in silicon. This structure is then void-free filled with nickel in the electroplating process. The combination of electrochemical etching and electroplating techniques opens a route for the fabrication of large-scale 3D-periodic metallic micro-structures.

  • 3D metallo-dielectric structures combining electrochemical and electroplating techniques

     Hernández García, David; Lange, Diego; Todorov Trifonov, Trifon; Garin Escriva, Moises; Garcia Molina, Francisco Miguel; Rodriguez Martinez, Angel; Alcubilla Gonzalez, Ramon
    Micro Nano Engineering
    Presentation's date: 2009-09
    Presentation of work at congresses

    View View Open in new window  Share Reference managers Reference managers Open in new window

  • Tecnologia y caracterizacion de capas finas de silicio y germanio am

     El Gharandi, Mohamed El Rafik; Molinas Mata, Pau; Garcia Molina, Francisco Miguel; Calderer Cardona, Josep
    MICROELECTRONICA 92. TECNOLOGIAS, DISEÑO, APLICACIONES.
    Presentation of work at congresses

     Share Reference managers Reference managers Open in new window