A5081134128- GaN-based semiconductor devices and materials
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Electrostatic Discharge in Electronics
- Physical Unclonable Functions (PUFs) and Hardware Security
- Semiconductor materials and interfaces
- Industrial Gas Emission Control
- Advancements in Semiconductor Devices and Circuit Design
- Cold Atom Physics and Bose-Einstein Condensates
- Thin-Film Transistor Technologies
- Silicon Carbide Semiconductor Technologies
- Advanced Frequency and Time Standards
- Thermochemical Biomass Conversion Processes
- Radiation Effects in Electronics
- Silicon and Solar Cell Technologies
- ZnO doping and properties
- Minerals Flotation and Separation Techniques
- Advanced Optical Sensing Technologies
- Gas Sensing Nanomaterials and Sensors
- Material Properties and Applications
- solar cell performance optimization
- Photovoltaic System Optimization Techniques
University of Cagliari
2015-2024
University of Siena
2024
University of Padua
2013
Heinrich Heine University Düsseldorf
2012-2013
Sardegna Ricerche (Italy)
2008-2012
Kirchhoff (Germany)
2011
Ferdinand-Braun-Institut
2011
Short-term accelerated life test activity on high brightness light emitting diodes is reported. Two families of 1-W light-emitting (LEDs) from different manufacturers were submitted to distinct stress conditions: temperature storage without bias and dc current test. During aging, degradation mechanisms like output decay electrical property worsening detected. In particular, the in efficiency induced by thermal was found follow an exponential law, activation energy process extrapolated. Aged...
By means of a statistical analysis, the soft breakdown and hard thin gate SiO/sub 2/ films in MOS devices are shown to have common physical origin. Being triggered by identical microscopic defects, these modes can be actually considered same failure mechanism. In particular, it is that conduction path not precursor final event, which generally appears at different spatial location. The huge differences between post-breakdown current-voltage (I-V) characteristics attributed spot area point...
The use of ultra-precise optical clocks in space ("master clocks") will allow for a range new applications the fields fundamental physics (tests Einstein's theory General Relativity, time and frequency metrology by means comparison distant terrestrial clocks), geophysics (mapping gravitational potential Earth), astronomy (providing local oscillators radio ranging interferometry space). Within ELIPS-3 program ESA, "Space Optical Clocks" (SOC) project aims to install operate an lattice clock...
This paper presents an extensive study of how a solar cell with low shunt resistance can affect the performance and reliability panel. The analysis is based on both simulations experimental tests provides following results: 1) significantly reduces efficiency panel; 2) this particularly pronounced if shunted partially shaded: in case, acts as load for entire 3) these conditions, degrade: fact, small-size paths are crossed by high current density, generated other cells panel, thus reaching...
This paper presents failure modes observed in long-term aging of high-brightness GaN/InGaN LEDs. The blue LEDs submitted to DC test present large decrease emitted optical power and increase diode reverse leakage current. Increase parasitic series resistance, suggesting contact degradation, has also been found stressed sample, together with apparent carrier density increases reduction the junction depletion width. Furthermore modification a specific trap property: activation energy decreases...
In this paper we report the analysis of thermal stability High Brightness Light Emitting Diode subjected to and bias ageing. The degradation mechanisms several families commercial available devices were investigated. first part work estimated resistance behaviour under dc condition. After characterisation two different ageing tests carried out on devices: aging at high temperature levels without biasing accelerated stress nominal current value (400mA). At each step a complete electrical...
We present an investigation of the degradation InGaN/GaN laser diodes grown on a GaN substrate. The results indicate that: (i) Ageing induces significant increase in threshold current (Ith) lasers, which is attributed to non-radiative recombination; (ii) Ith correlated decrease micro-cathodoluminescence signal measured (after removal top metallization) region under ridge; (iii) micro-photoluminescence measurements that constant stress increases recombination within quantum wells (and not...
This work has studied the effect of pH on specific growth rate mu, yield factor Y, and substrate consumption U for two mixed microbial populations (sludge A B) in a batch reactor with limiting (phenol). The mathematical analysis mu as function been applied not only to results present but also other published data. On basis obtained, following remarks can be made: (a) bacterial activity differed sludges; (b) variations one unit more or less than optimum give rise appreciable U; (c) regard...