A5010920390- Silicon Nanostructures and Photoluminescence
- Semiconductor materials and devices
- Nanowire Synthesis and Applications
- Ion-surface interactions and analysis
- Analytical Chemistry and Sensors
- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Electrochemical Analysis and Applications
- Electron and X-Ray Spectroscopy Techniques
- CCD and CMOS Imaging Sensors
- Energy Efficient Wireless Sensor Networks
- Advanced biosensing and bioanalysis techniques
- Transition Metal Oxide Nanomaterials
- Conducting polymers and applications
- Semiconductor materials and interfaces
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Solar and Space Plasma Dynamics
- Water Quality Monitoring Technologies
- Adaptive optics and wavefront sensing
- Advanced Chemical Sensor Technologies
- Analog and Mixed-Signal Circuit Design
- Infrared Target Detection Methodologies
- Biosensors and Analytical Detection
- Energy Harvesting in Wireless Networks
Morelia Institute of Technology
2024
Universitat de Barcelona
2010-2022
Universitat Autònoma de Barcelona
2008
Departament de Salut
2000
Lockheed Martin (United States)
1981-1983
The correlation between the structural (average size and density) optoelectronic properties [band gap photoluminescence (PL)] of Si nanocrystals embedded in SiO2 is among essential factors understanding their emission mechanism. This has been difficult to establish past due lack reliable methods for measuring distribution from electron microscopy, mainly because insufficient contrast SiO2. With this aim, we have recently developed a successful method imaging matrices. done by using...
The ability of surface passivation to enhance the photoluminescence (PL) emission Si nanocrystals in SiO2 has been investigated. No significant increase average nanocrystal size detected for annealings at 1100 °C between 1 min and 16 h. In contrast, PL intensity steadily increases reaches saturation after 3–4 h annealing time. Such behavior shows an inverse correlation with amount dangling bonds (Pb centers) interface matrix. A postannealing 450 forming gas enhances lifetime, due a reduction...
The size distribution, band gap energy, and photoluminescence of silicon nanocrystals embedded in SiO2 have been measured by direct independent methods. distribution is coupling high-resolution conventional electron microscopy special imaging conditions. calculated from excitation measurements agrees with theoretical predictions. Their correlation allows us to report the experimental Stokes shift between absorption emission, which 0.26±0.03 eV, average size. This almost exactly twice energy...
Field effect induced luminescence has been achieved by alternate tunnel injection of electrons and holes into Si nanocrystals. The emitting device is a metal-oxide-semiconductor structure with semitransparent polycrystalline contact ∼250nm thick silicon-rich silicon oxide layer about 40nm deposited on p-type substrate plasma-enhanced chemical vapor deposition. electroluminescence optimized for excess 17% annealing at 1250°C 1h in nitrogen-rich atmosphere. pulsed emission presents typical...
Ion implantation followed by high temperature annealing can be used to synthesize group IV semiconducting nanoparticles in SiO2. The density and the size distribution of these nanocrystals obviously depend on conditions. While their measured “classical” transmission electron microscopy techniques, cannot because no diffraction occurs amorphous matrix. In this letter, we use energy loss spectroscopy overcome problem. We have evolution distribution, density, atomic fraction occupied Ge...
Fabrication and organosilane-functionalization characterization of nanostructured ITO electrodes are reported. Nanostructured were obtained by electron beam evaporation, a subsequent annealing treatment was selectively performed to modify their crystalline state. An increase in geometrical surface area comparison with thin-film observed atomic force microscopy, implying higher electroactive for thus detection levels. To investigate the detectability, chemical performed. The formation...
In this paper, we present a practical application for wireless sensor networks (WSN): The sensing of the pH, NH4+ and temperature fish farm. Two different kinds modules were designed: Te module. module includes pH sensors based on specially designed ISFET. collects transmits information to by means 9600 b/s asynchronous wired communication. node, retransmit it central unit via RF. WSN follows standard IEEE 802.15.4 implements routing protocol Zigbee. aims work are (1) show ISFET developed...
In the last years number of papers related to wireless sensor networks has increased substantially. Most them focus in raising issues as routing algorithms, network lifetime, and more recently, Multiple Input Output networks. contrast with all those studies, we present a practical application networks: The sensing pH temperature for fish farm. requires two different kind modules: itself module. collect transmit information module using wired connection. Once reaches node, it is forwarded...
In this letter, we report the ion-beam synthesis and structural characterization of ZnS nanocrystals in SiO2. Both electron diffraction x-ray measurements show precipitation having a wurtzite–2H structure infrared spectroscopy confirms presence Zn–S bonding. Upon annealing, transmission microscopy observations Ostwald ripening precipitates coupled with self-organization two layers parallel to free surface. This has been also detected by secondary ion mass spectroscopy, its origin is...
The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis redox active molecules. ITO films were fabricated using electron beam evaporation at different substrate temperatures and subsequently annealed promoting their crystallization. morphology deposited material was monitored scanning microscopy, confirming deposition either thin or nanowires, depending on temperature....
The performance of transparent nanostructured indium tin oxide electrodes prepared by electron beam evaporation is optimized for biosensing purposes.
In battery-operated nodes of a wireless sensor network, energy is scarce resource that should not be wasted. During the recent years, efficient algorithms and protocols to maximize network lifetime have attracted attention many researchers. As radio transceiver one elements node has higher power consumption, typical approach save minimize period time it active. That can achieved by introducing duty cycle in which periodically enables its for short later return an idle state. this paper, we...