Zener diode

Summary

A Zener diode is a special type of diode designed to reliably allow current to flow "backwards" (inverted polarity) when a certain set reverse voltage, known as the Zener voltage, is reached. Zener diodes are manufactured with a great variety of Zener voltages and some are even variable. Some Zener diodes have an abrupt, heavily doped p–n junction with a low Zener voltage, in which case the reverse conduction occurs due to electron quantum tunnelling in the short distance between p and n regions − this is known as the Zener effect, after Clarence Zener. Diodes with a higher Zener voltage have lighter doped junctions which causes their mode of operation to involve avalanche breakdown. Both breakdown types are present in Zener diodes with the Zener effect predominating at lower voltages and avalanche breakdown at higher voltages. They are used to generate low-power stabilized supply rails from a higher voltage and to provide reference voltages for circuits, especially stabilized pow

Official source

https://en.wikipedia.org/wiki/Zener_diode

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Charge sensing properties ofmonolithic CMOS pixel sensors fabricated in a 65 nm technology

Francesco Piro

In this work the initial performance studies of the first small monolithic pixel sensors dedicated to charged particle detection, called CE-65, fabricated in the 65nm TowerJazz Panasonic Semiconductor Company are presented. The tested prototypes comprise matrices of 64 x 32 square analogue-output pixels with a pitch of 15 mu m. Different pixel types explore several sensing node geometries and amplification schemes, which allows for various biasing voltage of the detection layer and hence depletion conditions and electric field shaping. Laboratory tests conducted with a Fe-55 source demonstrated that the CE-65 sensors reach equivalent noise charge in the 15 to 25 e(-) range and excellent charge collection efficiencies. Charge sharing is substantial for standard diodes, but can be largely suppressed by modifying their design. Depletion of the thin sensitive layer saturates at a reverse diode bias of about 5 V.

ELSEVIER2022

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This paper reports on the design and experimental verifications of a passive step-up rectifier for MEMS piezoelectric energy scavengers. The purpose of the proposed circuit is to improve system startup for vibration micro-generators without the need of an external source of energy. The design chosen is based on a voltage multiplier where conventional diodes are replaced by PMOS low-VT transistors. The circuit is produced in 1.8V 0.18μm UMC CMOS technology. Test and verifications were performed using a real piezo scavenger providing an AC voltage of 0 to 350mVpeak at a frequency of around 2.4 kHz. Up to 2V DC was measured at the output of the rectifier.

Cell Bench Research Center, KAIST2011

Evolution of the Morphology Near Triple-Phase Boundaries in Ni–Yttria Stabilized Zirconia Electrodes Upon Cathodic Polarization

Priscilla Caliandro, Marco Cantoni, Guillaume Jeanmonod, Arata Nakajo, Lucie Navratilova, Giorgio Rinaldi, Jan Van Herle

Microstructural changes in Ni–yttria stabilized zirconia (YSZ) near the YSZ electrolyte were examined by three-dimensional (3D) electron microscopy after electrolysis and fuel cell operation up to 10,700 h and 15,000 h, respectively. The depletion of Ni and three-phase boundaries (TPBs) close to the electrolyte was detected upon cathodic polarization. It corresponded to spatial variations of dihedral angles (θ) at TPBs and Ni surface curvature along the direction perpendicular to the electrolyte, which comport with electrowetting and Zener pinning theory on several aspects. θNi decreased by up to 6 deg next to the electrolyte after electrolysis but remained uniform after fuel cell operation. This is in line with predictions from electrowetting theory with capacitances measured by electrochemical impedance spectroscopy and distribution of relaxation times. The decrease in θNi was concurrent to transition toward concave Ni/pore interfacial shapes and lower genus of the Ni phase, which suggests the pinch-off of Ni ligaments following surface diffusion-controlled Rayleigh instability. The increase in absolute mean curvature near the electrolyte interface is a driving force for outward transport of Ni. The decrease in θYSZ further suggests that TPB lines relocate on YSZ surface features that provide higher Zener pinning force. In contrast, few localized contact losses between Ni and YSZ that can also occur under high cathodic polarization and trigger Ni depletion were detected. The results are expected to advance the understanding of the driving forces that cause Ni depletion near the electrolyte in electrolysis for the design of improved solid oxide cell electrode microstructures.

2020