RESUMEN

The manufacturing cost of quantum cascade lasers is still a major bottleneck for the adoption of this technology for chemical sensing. The integration of Mid-Infrared sources on Si substrate based on CMOS technology paves the way for high-volume low-cost fabrication. Furthermore, the use of Si-based fabrication platform opens the way to the co-integration of QCL Mid-InfraRed sources with SiGe-based waveguides, enabling realization of optical sensors fully integrated on planar substrate. We report here the fabrication and the characterization of DFB-QCL sources using top metal grating approach working at 7.4 µm fully implemented on our 200 mm CMOS pilot line. These QCL featured threshold current density of 2.5 kA/cm² and a linewidth of 0.16 cm-1 with a high fabrication yield. This approach paves the way toward a Mid-InfraRed spectrometer at the silicon chip level.

RESUMEN

Nanoelectromechanical systems (NEMS) resonators can detect mass with exceptional sensitivity. Previously, mass spectra from several hundred adsorption events were assembled in NEMS-based mass spectrometry using statistical analysis. Here, we report the first realization of single-molecule NEMS-based mass spectrometry in real time. As each molecule in the sample adsorbs on the resonator, its mass and position of adsorption are determined by continuously tracking two driven vibrational modes of the device. We demonstrate the potential of multimode NEMS-based mass spectrometry by analysing IgM antibody complexes in real time. NEMS-based mass spectrometry is a unique and promising new form of mass spectrometry: it can resolve neutral species, provide a resolving power that increases markedly for very large masses, and allow the acquisition of spectra, molecule-by-molecule, in real time.

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RESUMEN

We have developed arrays of nanomechanical systems (NEMS) by large-scale integration, comprising thousands of individual nanoresonators with densities of up to 6 million NEMS per square centimeter. The individual NEMS devices are electrically coupled using a combined series-parallel configuration that is extremely robust with respect to lithographical defects and mechanical or electrostatic-discharge damage. Given the large number of connected nanoresonators, the arrays are able to handle extremely high input powers (>1 W per array, corresponding to <1 mW per nanoresonator) without excessive heating or deterioration of resonance response. We demonstrate the utility of integrated NEMS arrays as high-performance chemical vapor sensors, detecting a part-per-billion concentration of a chemical warfare simulant within only a 2 s exposure period.

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Measurements of the gauge factor of suspended, top-down silicon nanowires are presented. The nanowires are fabricated with a CMOS compatible process and with doping concentrations ranging from 2 × 10(20) down to 5 × 10(17) cm(-3). The extracted gauge factors are compared with results on identical non-suspended nanowires and with state-of-the-art results. An increase of the gauge factor after suspension is demonstrated. For the low doped nanowires a value of 235 is measured. Particular attention was paid throughout the experiments to distinguishing real resistance change due to strain modulation from resistance fluctuations due to charge trapping. Furthermore, a numerical model correlating surface charge density with the gauge factor is presented. Comparison of the simulations with experimental measurements shows the validity of this approach. These results contribute to a deeper understanding of the piezoresistive effect in Si nanowires.

RESUMEN

We report an actuation/detection scheme with a top-down nanoelectromechanical system (NEMS) for frequency shift based sensing applications with outstanding performance. It relies on electrostatic actuation and piezoresistive nanowire gauges for in-plane motion transduction. The process fabrication is fully CMOS (complementary metal-oxide-semiconductor) compatible. The results show a very large dynamic range of more than 100 dB and an unprecedented signal to background ratio of 69 dB providing an improvement of two orders of magnitude in the detection efficiency presented in the state of the art in NEMS fields. Such a dynamic range results from both negligible 1/f noise and very low Johnson noise compared to the thermomechanical noise. This simple low power detection scheme paves the way for new class of robust mass resonant sensors.

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RESUMEN

We report a new transmission that can be used for quantum key distribution. The system uses single-sideband-modulated light in an implementation of the BB84 quantum cryptography protocol. The system is formed by two integrated unbalanced Mach-Zehnder interferometers and is based on interference between phase-modulated sidebands in the spectral domain. Experiments show that high interference visibility can be obtained.