0000000000385788
AUTHOR
A. Piana
Carrier-induced quenching processes on the erbium luminescence in silicon nanocluster devices
The luminescence-quenching processes limiting quantum efficiency in Er-doped silicon nanocluster light-emitting devices are investigated and identified. It is found that carrier injection, while needed to excite Er ions through electron-hole recombination, at the same time produces an efficient nonradiative Auger deexcitation with trapped carriers. This phenomenon is studied in detail and, on the basis of its understanding, we propose device structures in which sequential injection of electrons and holes can improve quantum efficiency by avoiding Auger processes. © 2006 The American Physical Society.
Design and development of a fNIRS system prototype based on SiPM detectors
Functional Near Infrared Spectroscopy (fNIRS) uses near infrared sources and detectors to measure changes in absorption due to neurovascular dynamics in response to brain activation. The use of Silicon Photomultipliers (SiPMs) in a fNIRS system has been estimated potentially able to increase the spatial resolution. Dedicated SiPM sensors have been designed and fabricated by using an optimized process. Electrical and optical characterizations are presented. The design and implementation of a portable fNIRS embedded system, hosting up to 64 IR-LED sources and 128 SiPM sensors, has been carried out. The system has been based on a scalable architecture whose elementary leaf is a flexible board …
Photonic-crystal silicon-nanocluster light-emitting device
We report on enhanced light extraction from a light-emitting device based on amorphous silicon nanoclusters, suitable for very-large-scale integration, and operating at room temperature. Standard low-cost optical lithography is employed to fabricate a two-dimensional photonic crystal onto the device. We measured a vertical emission with the extracted radiation enhanced by over a factor of 4, without the aid of any buried reflector. These achievements demonstrate that a cost-effective exploitation of photonic crystals is indeed within the reach of semiconductor industry and open the way to a new generation of nanostructured silicon devices in which photonic and electronic functions are integ…
Extensive electrical model of large area silicon photomultipliers
Abstract In this paper the full electrical model of silicon photomultipliers fabricated at STMicroelectronics Catania R&D clean room facilities is presented. An accurate investigation on both SiPM single microcell and entire SiPM structure to extrapolate all the electrical elements has been executed by means of dedicated characterizations carried out on appropriate layout structure. The electrical simulations results are compared to the experimental data showing a good fit and therefore verifying the accuracy of the proposed model. This model can be used to describe all the SiPMs with different sizes manufactured using the same technology. Moreover, starting from this extensive electrical m…
Electroluminescence and transport properties in amorphous silicon nanostructures
We report the results of a detailed study on the structural, electrical and optical properties of light emitting devices based on amorphous Si nanostructures. Amorphous nanostructures may constitute an interesting system for the monolithic integration of optical and electrical functions in Si ULSI technology. In fact, they exhibit an intense room temperature electroluminescence (EL), with the advantage of being formed at a temperature of 900 °C, while at least 1100 °C is needed for the formation of Si nanocrystals. Optical and electrical properties of amorphous Si nanocluster devices have been studied in the temperature range between 30 and 300 K. The EL is seen to have a bell-shaped trend …
Preliminary radiation hardness tests of single photon Si detectors
Single photon Si detectors were fabricated by STMicroelectronics and fully characterized in standard operation conditions and after irradiations. Both single cells and arrays, of dimensions ranging from 5x5 up to 64x64, were electrically tested. The devices operation was studied as a function of the temperature from -25 degrees C to 65 degrees C varying the voltage over breakdown, from 5% up to 20% of the breakdown voltage before and after irradiation using both light ions, 10 MeV B ions to doses in the range 3x10(7)-5x10(10) cm(-2), and X-rays irradiations in the range 0.5-20 krad(Si). Optical characterization was performed using a laser at 659 nm and opportunely chosen filters to vary the…
Clonal populations of hematopoietic cells with paroxysmal nocturnal hemoglobinuria phenotype in patients with splanchnic vein thrombosis
Abstract Introduction Splanchnic vein thrombosis (SVT) is a serious complication in patients with paroxysmal nocturnal hemoglobinuria (PNH). Mutant PNH clones can be associated with an increased risk of SVT even in the absence of overt disease, but their prevalence in non-selected SVT patients remains unknown. Materials and Methods Patients with objective diagnosis of SVT and without known PNH were tested for the presence of PNH clone using high-sensitivity flow cytometric analysis. Results A total of 202 SVT patients were eligible, 58.4% were males, mean age was 54.6 years (range 17–94), site of thrombosis was portal in 103 patients, mesenteric in 67, splenic in 37, and supra-hepatic in 10…