Electro-thermal characterization of AlGaN/GaN HEMT on Silicon Microstrip Technology

In this work an experimental assessment of the electro-thermal behaviour of AlGaN/GaN HEMT on HR-Si Microstrip Technology is given. Self-heating effects and temperature rise have been evaluated on 1 mm active device periphery when HR-Si is lapped down to 50 lm exploiting infrared thermal DC characterization method to validate thermal simulations. Maximum channel temperature and thermal resistance of the structure has been extracted at different power dissipation conditions. For the same device periphery, the Gate-to-Gate pitch influence has also been experimentally investigated and correlated to the channel temperature. Finally, relevant information about the maximum power dissipation has been pointed out, and an accurate description of the electro-thermal behavior observed experimentally is given

Trilayer electron-beam lithography and surface preparation for sub-micron Schottky contacts on GaAs heterostructures

Foreseen operation at sub-THz frequencies of Schottky contacts for diodes and transistor gates on GaAs based heterostructures requires area reduction down to 0.1×1 microns, and wet chemical processes. We report on the compatibility of Trilayer Electron-beam Lithography with such wet processes. © 2010 IEEE

Antenna-coupled heterostructure field effect transistors for integrated terahertz heterodyne mixers

We present the realization of high electron mobility transistors on GaN-heterostructures usable for mixing and rectification in the THz range. Device fabrication is fully compatible with industrial processes employed for millimetre wave integrated circuits. On-chip, integrated, polarization- sensitive, planar antennas were designed to allow selective coupling of THz radiation to the three terminals of field effect transistors in order to explore different mixing schemes for frequencies well above the cutoff frequency for amplification. The polarization dependence of the spectral response in the 0.18-0.40 THz range clearly demonstrated the possible use as integrated heterodyne mixers. © 2013 Copyright SPIE

AlGaN/GaN heterostructure transistors for the generation and detection of THz radiation

The AlGaN/GaN heterostructure is an excellent candidate for the realization of sub-millimeter wave power amplifiers, which can serve as integrated power source for THz frequency multipliers. Here we discuss the operation of AlGaN/GaN transistors as THz detector, which provides information on the behavior of the electron system at THz frequencies. © 2010 IEEE

Study of the Coupling of Terahertz Radiation to HeterostructureTransistors with a Free Electron Laser Source

High electron mobility transistors can work as room-temperature directdetectors of radiation at frequency much higher than their cutofffrequency. Here, we present a tool based on a Free Electron Lasersource to study the detection mechanism and the coupling of the highfrequency signal into the transistor channel. We performed a mappingover a wide area of the coupling of 0.15 THz radiation to an AlGaN/GaNtransistors with cut-off frequency of 30 GHz. Local,polarization-dependent irradiation allowed us to selectively couple thesignal to the channel either directly or through individual transistorbias lines, in order to study the nonlinear properties of thetransistor channel. Our results indicate that HEMT technology can beused to design a millimeter-wave focal plane array with integratedplanar antennas and readout electronics

Perspectives in the design of monolithic focal plane arrays for terahertz active spectroscopic imaging

Active spectroscopic imaging is based on arrays of broadband, short-response-time detectors observing a scene illuminated by a number of THz sources. Here we present the system design, the fabrication process and the single-pixel test for three detector technologies: GaAs Schottky diodes, GaN transistors, Nb bolometers. © 2010 IEEE

Diagnostic and infection control strategies for Clostridioides difficile infections in a setting of high antimicrobial resistance prevalence

Clostridioides difficile (CD) is a major nosocomial pathogen and the leading cause of antibiotic-associated diarrhoea. In light of the strong association between antimicrobial use and CD infections (CDI), it may be hypothesised that areas at higher prevalence of antimicrobial resistance, like the region of Campania in southern Italy, could also have a higher rate of CDI. In this multicentre, region-based, prospective study, we analysed such issues, exploiting CDI incidence data collected from local hospitals. In 2016, the Italian National Centre for Disease Control supported a project involving three Italian regions: Friuli Venezia Giulia, Lazio and Campania. In Campania, a network of 49 hospitals willing to participate in the project was created. The project consisted of two phases: a survey on practice patterns concerning CDI and an epidemiological surveillance study. We identified a stringent need to improve awareness about CDI among the regional health-care community, as a widespread lack of surveillance programmes for CDI control was observed (existing in only 40% of participating facilities). Moreover, almost half of the participating hospitals (n=16, 43%) had no standardised procedures or protocols to control and prevent CDI. In the second phase of the study, we collected data of CDI cases during a six-month surveillance programme. In all, 87 CDI cases were observed, for a total of 903,334 patient bed-days and 122,988 admissions. According to the above data, CDI incidence was 0.96 cases/10000 patient bed-days, much lower than expected based on prior studies conducted elsewhere. The results of our study suggest CDI remains a rather neglected clinical issue in Campania. Despite a high burden of antimicrobial resistance and antimicrobial use in our geographic setting, we observed a very low incidence of CDI. Such a low incidence could be explained by underdiagnosis, but could also be related to actual diet, the lower patient age or the specific genetic background. However, further studies are warranted to either confirm or rebut the above hypotheses