Silicon carbide (SiC) is a widely used material in several industrial applications such as high power electronics, light emitting diodes, and in research application such as photo-voltaic and quantum technologies. As nanoparticles it can be synthetised in many sizes and different polytypes from 200 nm down to 1 nm. In the form of quantum dots they are used as optical biomarkers, and their emission, occurring from the blue to the orange spectral region, is based on quantum confinement effect. In this work we report on emission in the red and near infrared in different SiC polytypes, specifically in 4H, 6H and 3C. In 4H SiC the red visible emission yielded non classical light attributed to an intrinsic defect, identified as a carbon-antisite vacancy pair. Similar spectral emission was observed in 3C SiC bulk and nanoparticles, also yielding very bright single photon emission. Emission in the far red has been observed in homogeneous hetero-structure in SiC tetrapods.
Optical and paramagnetic deep defects in silicon carbide (SiC) offer a vast opportunity to realize advanced quantum device and sensors based on SiC bulk material and SiC nanostructures. Nanostructures in silicon carbide such as nanoparticle and quantum dots possess strong sub-bandgap emission due to both quantum confinement and radiative recombination in deep defects, making them ideal as bio-markers. We will highlight silicon carbide extremely rich underlying resources, ideal for the implementation of next generation nanophotonics and spintronics quantum devices and related biomedical applications. Specifically, we show here the isolation of intrinsic defects in SiC achieved by electron irradiation of the material, yielding single photon emission.
Significant advancements in photovoltaic solar cells are required to support large-scale energy demands with solar power. The first generation of solar cells (SC) available today uses Si. While Si is highly abundant and these types of SC can be easily manufactured, the best power conversion efficiency is only 24%. Developing photovoltaic SC using III-V materials may increase the efficiency while decreasing the manufacturing costs associated with cell fabrication. This paper studies the opportunity to improve two-junctions solar cells made of III-V materials by making the layers very thin and including the antireflective layer in the first junction. In terms of light harvesting, the anti-reflective layer made of a semiconductor is shown to absorb the most part of the incident light.