A 512 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 16 single photon avalanche diode (SPAD)-based line sensor is designed in a 0.13-<inline-formula> <tex-math ...notation="LaTeX">\mu \text{m} </tex-math></inline-formula> CMOS image sensor technology for time-resolved multispectral beam scanned imaging. The sensor has 23.78-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> pixel pitch and incorporates one SPAD array with 49.31% fill factor optimized for detection in the blue-green spectral region, and a second array at 15.75% fill factor optimized for the red-near-infrared response spectral region. Each pixel contains a 32-bin histogramming time-to-digital converter (TDC) with a mean time resolution of 51.20 ps. Histogram bin resolutions are adjustable from 51.20 ps to 6.55 ns per bin. The line sensor can operate in single photon counting (SPC) mode (102.1 giga-events/s), time-correlated SPC (TCSPC) mode (192.4 million-events/s) or on-chip histogramming mode (16.5 giga-events/s), increasing the count rate up to 85 times compared to TCSPC mode. Sensor capability is demonstrated through spectral fluorescence lifetime imaging, resolving three fluorophore populations with distinct fluorophore lifetimes.
Infineon’s 5th Generation of 1200V SiC diodes uses a new compact chip design, realized by an optimized hexagonal merged-pn cell structure in the active area. This allows a higher n-doping in the epi ...layer due to improved E-field shielding resulting in a smaller differential resistance per chip area. Thanks to the merged-pn cell structure, depending on the diode ampere rating, a surge current capability now rated up to 14 times the nominal current ensures robust diode operation during surge current events in the application. The previous generations of 1200V SiC diodes could not make full use of the high breakdown field strength of the SiC material due to the instable avalanche which occurs at the edge termination only, and therefore, requiring a significant safety margin between rated voltage and breakdown voltage. Now the 5th Generation is designed in a way that each cell contributes to the avalanche, enabling a much more avalanche rugged device.
A linearly polarized (LP) wave with an arbitrary polarization plane is generated by combining left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) waves radiated from ...a dual-circularly polarized patch antenna. The polarization plane of the LP wave is continuously controlled by changing the phase difference between the LHCP and RHCP waves by using variable phase shifters composed of a quadrature hybrid and varactor diodes. Experimental results show that the polarization plane rotates continuously from -95° to 107° with a cross-polarization discrimination kept better than 22 dB in the boresight direction at 5.2 GHz.
We have demonstrated a wide radiation temperature measurement by using a single photon avalanche diode (SPAD) image array that is analogous to a Silicon Photomultiplier with a time-gating technique ...and an adjustable summed output. The detection temperature window ranging from 280 °C to 1050 °C can be achieved with a noise equivalent temperature difference value (NETD) below 1 °C. Thermal image with a high detection rate up to 1680 Hz is obtained at the same detection temperature with a commercial CMOS thermal camera. We further demonstrate a thermal image with a spatial resolution of 80 μm.
Herein, the Ni/SiO
2
/p-Si MIS diode was developed via the liquid phase epitaxy (LPE) process. The structural and surface morphology were investigated by XRD and SEM techniques. The electrical study ...of the device, Ni/SiO
2
/n-Si, demonstrates a worthy rectification and the electrical parameters of the Schottky diode have computed using the
I-V
characterization. Different dielectric parameters as capacitance (
C
), permittivity (
ε’
), dielectric loss (
ε”
), conductance and ac conductivity (
σ
ac
) were evaluated. Moreover, their relation to bias dc voltage has been examined in the frequency range 10 Hz–20 MHz, temperature 303 K to 363 K and DC bias voltage from -2 V to 2 V. Also, the variable investigated parameters were found to be dependent upon temperature, frequency and bias voltage.
We report on the demonstration of MOVPE-grown single nanowire InGaN/GaN core–shell light emitting diodes (LEDs) with a transparent graphene contact for hole injection. The electrical homogeneity of ...the graphene-contacted LED has been assessed by electron beam induced current microscopy. By comparing graphene-contacted and metal-contacted nanowire LEDs, we show that the contact layout determines the electroluminescence spectrum. The electroluminescence changes color from green to blue with increasing injection current. High-resolution cathodoluminescence on cleaved nanowires allows the location with high precision of the origin of different emitted wavelengths and demonstrates that the blue peak originates from the emission of the radial quantum well on the m-planes, whereas the green peak arises from the In-rich region at the junction between the m-planes and the semipolar planes. The spectral behavior of the electroluminescence is understood by modeling the current distribution within the nanowire.
Three-diode lumped-parameter equivalent circuit model conforms to photovoltaic device physics and processes an exact analysis for <inline-formula> <tex-math notation="LaTeX">{I} ...</tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V} </tex-math></inline-formula> characteristics of industrial solar cells, because it explains the different leakage current components especially for recombination current resulting from defects or grain boundaries. However, three-diode model's complete circuit topology leads to complicated transcendental <inline-formula> <tex-math notation="LaTeX">{I} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V} </tex-math></inline-formula> equation without analytical solution so that low computation efficiency limits three-diode model's applications in photoelectric simulations. In this article, an effective-diode method is proposed to simplify three-diode model, derive accurate and efficient terminal current-voltage solution to three-diode model, and acquire electrostatic characteristics of the solar cells. The calculated values have good agreements with numerical iteration results and experimental data measured from solar cells, respectively. Finally, the effective-diode method performs an important role of solving three-diode model analytically, predicting <inline-formula> <tex-math notation="LaTeX">{I} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V} </tex-math></inline-formula> characteristics of industrial solar cells accurately, and providing three-diode model's practicability and development in solar cells' simulations.
Metasurfaces (MSs) have enabled the emergence of new ideas and solutions in the design of antennas and for the control of electromagnetic waves. In this work, we propose to design a directional ...high-gain reconfigurable planar antenna based on a phase-modulated metasurface. Reconfigurability is achieved by integrating varactor diodes into the elementary meta-atoms composing the metasurface. As a proof of concept, a metasurface prototype that operates around 5 GHz is designed and fabricated to be tested in an antenna configuration. The metasurface is flexibly controlled by different bias voltages applied to the varactor diodes, thus allowing the user to control its phase characteristics. By assigning judiciously calculated phase profiles to the metasurface illuminated by a feeding primary source, different scenarios of far-field patterns can be considered. Different phase profiles are tested, allowing us to, firstly, achieve a highly directive boresight radiation and, secondly, to steer the main radiated beam towards an off-normal direction. The whole design process is verified by numerical simulations and is validated experimentally by far-field antenna measurements. The proposed metasurface enables the design of directive flat antennas with beam-scanning characteristics without complex feeding systems and power-consuming phase shifters, and thus provides potential interests for next generation antenna hardware.
In this paper, a new medium voltage power converter topology using a diode rectifier, three-level boost (TLB) converter, and neutral-point-clamped (NPC) inverter is proposed for a high-power ...permanent magnet synchronous generator-based wind energy conversion system. The generator-side TLB converter performs the maximum power point tracking and balancing of dc-link capacitor voltages, while the grid-side NPC inverter regulates the net dc-bus voltage and reactive power to the grid. A significant improvement in the grid power quality is accomplished as the NPC inverter no longer controls the dc-link neutral point voltage. A model predictive strategy is proposed to control the complete system where the discrete-time models of the proposed power electronic converters are used to predict the future behavior of control variables. These predictions are evaluated using two independent cost functions, and the switching states which minimize these cost functions are selected and applied to the generator- and grid-side converters directly. In order to comply with the high-power application, the switching frequencies of the TLB converter and NPC inverter are minimized and maintained below 1.5 and 1 kHz, respectively. The proposed topology and control strategy are verified through MATLAB simulations on a 3-MW/3000-V/577-A system and dSPACE DS1103-based experiments on 3.6-kW/208-V/10-A prototype.
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It was still a great challenge to design high performance of rectification characteristic for the rectifier diode. Lately, a new approach was proposed experimentally to tune the ...Schottky barrier height (SBH) by inserting an ultrathin insulated tunneling layer to form metal–insulator-semiconductor (MIS) heterostructures. However, the electronic properties touching off the high performance of these heterostructures and the possibility of designing more efficient applications for the rectifier diode were not presently clear. In this paper, the structural, electronic and interfacial properties of the novel MIS diode with the graphene/hexagonal boron nitride/monolayer molybdenum disulfide (GBM) heterostructure had been investigated by first-principle calculations. The calculated results showed that the intrinsic properties of graphene and MoS2 were preserved due to the weak van der Waals contact. The height of interfacial Schottky barrier can be tuned by the different thickness of hBN layers. In addition, the GBM Schottky diode showed more excellent rectification characteristic than that of GM Schottky diode due to the interfacial band bending caused by the epitaxial electric field. Based on the electronic band structure, we analyzed the relationship between the electronic structure and the nature of the Schottky rectifier, and revealed the potential of utilizing GBM Schottky diode for the higher rectification characteristic devices.
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