Giovanni Pangallo

4H-SiC p-i-n diode as Highly Linear Temperature Sensor

The linear dependence on temperature of the voltage drop VD across a forward-biased 4H-SiC p-i-n diode is investigated experimentally. The results show that the fabricated temperature sensor has a high degree of linearity in the range from room temperature up to 573 K corresponding to a root-mean-square error lower than 0.5%. A maximum sensitivity of 2.66 mV/K was calculated. The low saturation current of the p-i-n diode, well below the forward biasing current also at high temperatures, reduces the nonlinear effects in the VD-T characteristic allowing the design and fabrication of highly linear sensors operating in a wider temperature range.

High-Performance Temperature Sensor Based on 4H-SiC Schottky Diodes

A high-performance temperature sensor based on coupled 4H-SiC Schottky diodes is presented. The linear dependence on temperature of the difference between the forward voltages appearing on two diodes biased at different constant currents, in a range from 30 °C up to 300 °C, was used for temperature sensing. A high sensitivity of 5.11 mV/°C was measured. This is, to the best of our knowledge, the first experimental result about a proportional-to-absolute-temperature sensor made with SiC diodes, showing both a good degree of linearity and long-term stability performance.

Highly Linear Temperature Sensor Based on 4H-Silicon Carbide p-i-n Diodes

The linear dependence on temperature of the voltage drop difference measured on two diodes biased at different constant currents has been characterized in a range from room temperature up to 573 K. The realized proportional to absolute temperature sensor shows a good level of linearity and the corresponding rms error lower than 0.3%. Moreover, a maximum sensitivity of 610 μV/K has been obtained, with an extrapolated output converging to 0 V at T = 0 K, in agreement with theory and allowing a single-point temperature calibration.

Integrated Amorphous Silicon p-i-n Temperature Sensor for CMOS Photonics

Hydrogenated amorphous silicon (a-Si:H) shows interesting optoelectronic and technological properties that make it suitable for the fabrication of passive and active micro-photonic devices, compatible moreover with standard microelectronic devices on a microchip. A temperature sensor based on a hydrogenated amorphous silicon p-i-n diode integrated in an optical waveguide for silicon photonics applications is presented here. The linear dependence of the voltage drop across the forward-biased diode on temperature, in a range from 30 °C up to 170 °C, has been used for thermal sensing. A high sensitivity of 11.9 mV/°C in the bias current range of 34–40 nA has been measured. The proposed device is particularly suitable for the continuous temperature monitoring of CMOS-compatible photonic integrated circuits, where the behavior of the on-chip active and passive devices are strongly dependent on their operating temperature.

85–440 K Temperature Sensor Based on a 4H-SiC Schottky Diode

The performance of a 4H-SiC Schottky diode for thermal sensing in the wide temperature range from T = 85 up to 443 K is presented. The linear dependence on temperature of the forward voltage drop, for different bias currents, is investigated through an analytical study of the temperature-dependent physical Schottky diode parameters. A high sensitivity of 1.18 mV/K was observed for a constant bias current of ID = 80 μA. The device exhibits a good degree of linearity with a calculated root mean square error, with respect to the best-linear fitting model, lower than 2.7 mV. Moreover, the proposed sensor shows a good repeatability maintaining a stable output over more cycles of measurements, from (down to) 85 up to (from) 443 K, in a long period of time.

SPICE modelling and experiments on a complete photovoltaic system including cells, storage elements, inverter and load

The design of a complete photovoltaic (PV) system and the precise evaluation of its performances under different conditions requires the use of an accurate simulation model. In this work, a SPICE model of a complete PV system, including a detailed model of PV cells and a multilevel inverter with load and energy storage elements, is presented. The simulation of the system as a whole allows determining the role of components and parameters as solar irradiation and cell temperature on the system performance. The global conversion efficiency and the total harmonic distortion (THD) of the output waveform are analysed in detail. The role and sizing criteria of storage elements placed in parallel with the PV modules are also analysed for various operating conditions. A PV system, including a specifically designed multilevel inverter, was built to perform efficiency and THD measurements that were compared with the simulation results to evaluate the model effectiveness.

V2O5/4H-SiC Schottky diode as a high performance PTAT sensor

A proportional to absolute temperature sensor (PTAT) based on V₂O₅/4H-SiC (divanadium pentoxide/4H polytype of silicon carbide) Schottky diodes is presented. The linear dependence between the voltage differences across two constant-current forward biased diodes on temperature has been used for thermal sensing in the wide temperature range from T=147 K up to 400 K. A sensitivity of 307 μV/K was calculated for two constant bias currents, I_D1=16 μA and I_D2=608 μA.

Voltage doubler rectifier based on 4H-SiC diodes for high-temperatures energy harvesting applications

A voltage doubler rectifier for hostile environments, in particular at high temperatures, is presented. The system consists of a clamper section and a single diode rectifier working at higher temperatures with respect to the conventional operating thermal domain of silicon electronics. Both sections are realized with integrated 4H-SiC Schottky diodes. The rectified output amplitude signal voltage increases with the temperature due to the corresponding diode threshold voltage lowering.

High perfomance integrated temperature sensor based on amorphous silicon diode for photonics on CMOS

A temperature sensor based on a photonic layer-integrated hydrogenated amorphous silicon p-i-n diode is presented. The linear dependence of the voltage drop across the forward-biased diode on temperature, in a range from 30 °C up to 170 °C, has been used for thermal sensing. A high sensitivity of 11.9 mV/°C in a biasing current range ≈34–40 nA has been measured.

Piezoelectric energy harvesting system for hostile environments

An energy harvester operating at high temperature, up to T=300 °C, is presented. In particular, a voltage doubling rectifier realized with two 4H-SiC Schottky diodes is used to rectify the AC voltage output of a piezoelectric bimorph with a Curie temperature of TC=320 °C. The rectifier efficiency is of about η~89% and it slightly increases with temperature due to the corresponding diodes threshold voltage decrease.