This paper reports on the fabrication and characterization of a passive silicon microfabricated direct methanol fuel cell (lDMFC). The main characteristics of the device are its capability to work without complex pumping systems, only by capillary pressure, and the fact that its performance is not affected by the device orientation. A simple fabrication process based in deep reactive ion etching (DRIE), allows obtaining a reliable and lowcost final device. The device consists of two silicon microfabricated plates mounted together with a commercial membrane electrode assembly (MEA). The impact of current collector design on microfuel cell performance is explored and current-voltage (I-V) and current-power (I-P) curves of the device at different methanol concentration and orientation are presented. Optimal performance was obtained for methanol concentrations between 3 and 5 M, achieving a maximum power density of 12 mW/cm 2 . The results obtained in this work demonstrate the feasibility of the device and give a guideline for design and conditions optimization.

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We present theoretical calculations using DFT method and the Global Reaction Model (GRM) for molecular structures and photoluminescence (PL) and Fourier Transform Infrared (FTIR) spectroscopy for silicon nanoclusters (Si-NCs) embedded in silicon rich oxide (SRO) films. Correlations between theoretical predictions and experimental results are made taking as reference experimental results obtained from measurements performed on SRO thin films obtained by the Hot Filament Chemical Vapor Deposition (HFCVD) technique. Our theoretical predictions are general since they do not depend on the particular technique used to obtain such films but rather the suggested SinOn structures. A good correlation exists for Eg values for films grown at 1300°C corresponding to Si 8 O 8 and Si 16 O 16 molecular structures suggested and for films grown at 1150°C with Si 9 O 9. Regards PL correlation, a film grown at 900°C gives a spectrum peaked at 440nm and 548nm while theoretical one shows peaks at 471nm and 549.8 nm for a structure Si 16 O 16. Such sample with a further annealing displays peaks at 405nm, 749nm and 820nm with theoretical predictions at 415nm using Si 6 O 6. As for FTIR, theoretical calculations predict vibrational mode frequencies of bonds Si-O and Si-H whose values are well located in the experimental frequency range corresponding to the structure Si 16 O 16 .