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Studies have demonstrated the remarkable properties of nanoparticles and their many applications due to their size. While conventional synthesis of nanoparticles including physical and chemical methods has proven to be very expensive and sources of environmental pollution and potential health problems, harmless and eco-friendly nanoparticles were obtained by the green approach from biological materials and were used in many sectors of activities. Zinc oxide nanoparticles (ZnONPs) have been recently the subject of intense studies due to their innumerable advantages, among which the most remarkable are their wide band gap, high excitonic binding energy, biocompatibility, and stability. ZnONPs were used for the antimicrobial, antifungal, anti-diabetic, anti-inflammatory, and antioxidant activities, the improvement of agriculture and food industry, and that of photovoltaic devices and storage. This review focuses on the green synthesis of ZnONPs from different biological materials, their characterization, and their potential applications. This review provides a better understanding of the biosynthesis, characterization techniques, and applications of ZnONPs in various sectors of activity. [ABSTRACT FROM AUTHOR]

We investigated the structural and optoelectronic properties of p-n germanium nanocrystals based junctions embedded between GaAs substrate and layers of ZnO:Al or a-Si:H. Scanning electron microscopy and scanning tunneling microscopy were used on these junctions in this work. Calculations of tunneling current on the substrate showed effect of localized defects trapping Fermi level at the surface tending to make a semi-insulating substrate. The average value of the diameter of the Ge nanoparticle is around 12.5 nm. These results lay the foundation for the development of solar cells which active part is made of GeNCs. [ABSTRACT FROM AUTHOR]

Quantum Cascade Lasers (QCLs) represent advanced technology for Mid-Infra Red (MIR) and Far-Infra Red (FIR) laser sources. Experiments were conducted to investigate the optical and electrical characteristics of Alpes SB 1487 QCLs. The laser source achieved pulsed power density on a target cavity with tunability around 7m. Measurements of the tunability of the QCLs as function of temperature and applied voltage were investigated to identify the shift in emission wavelength. The results indicated tunability as low as 0.04 nm/V with the pulse voltage and 0.28 nm/K with the sink temperature, respectively, at emission wavelength of ~ 6.8μm. The characteristics of QCLs confirmed the suitability for applications in bio-sensing and muonic atom spectroscopy. [ABSTRACT FROM AUTHOR]