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We present a butt-coupled InGaN fiber Bragg grating (FBG) semiconductor laser diode operating below 400 nm in the single-mode emission regime. This compact coherent laser source exhibits an intrinsic linewidth of 14 kHz in the near-UV range and a side-mode suppression ratio reaching up to 40 dB accompanied by almost 2 mW output power. Furthermore, the properties of the FBG, including its central wavelength, bandwidth, and reflectivity, can be readily customized to fulfill specific requirements. As a result, the small footprint design of this laser is compatible with integration into a standard butterfly package to ease the lab-to-market technology transfer. The combination of low-frequency noise and fibered output signal positions these FBG laser systems as strong candidates for hybridization with integrated photonic platforms tailored for quantum information processing and metrology. [ABSTRACT FROM AUTHOR]

Materials with tunable properties are often in the focus of materials science. Up to this point four different semiconducting materials and substitution variants have been found that are capable of switching between p‐ and n‐type conduction by a simple change in temperature. In this review, we illustrate previous findings of these pnp‐switching materials and current developments in functional implementations. While in the past decade, the scientific focus was primarily on discovering new materials that possess this intriguing switching effect, recently the first devices were successfully constructed and tested. Using the compounds, Ag18Cu3Te11Cl3 and AgCuS, that exhibit the pnp‐switching behaviour at approximately room temperature and 364 K, respectively, two single‐material diodes were developed and characterized. The approach for inducing this effect is denoted and the fundamental principles for realizing these devices are summarized. [ABSTRACT FROM AUTHOR]

In the present work, Al-doped (0, 1, 2 and 3%) ZnO nanoparticles (NPs) are synthesised by green combustion method (GCM) using Terminalia Catappa seeds (TCS) extract as a novel fuel. For the synthesis Zinc nitrate and Aluminum nitrate are used as precursor and dopant respectively. The synthesised NPs are characterised by XRD, FTIR, UV-vi and impedance spectroscopy. The XRD analysis shows decrease in crystallite size varies between 40 to 26 nm as dopant increases. The FTIR spectrum reaffirms the formation of Zn-O bonding structure at 454.28 cm−1. UV-Vi spectroscopic studies show the optical band gap of 3.63, 3.53, 3.22 and 3.19 eV for Al doped (0, 1, 2 and 3%) ZnO NPs. Thermal analysis for the synthesised Al-doped (0, 1, 2 and 3%) ZnO nanoparticles are analysed using TGA/DTA studies. The Electrical characteristics are studied at various temperatures (50 to 350°C) by varying frequency (10 Hz to 8 MHz). In low frequency regions, dielectric constant and dielectric loss increases with rise in temperature. The constant AC conductivity is observed in lower frequencies and increases for higher frequencies for all doped ZnO NPs. ZnO NPs prepared with 2% of doping exhibit improved structural and electrical properties. Hence these ZnO NPs may be used as sensing material for vibration sensor. Highlights: This paper focus on green synthesis of undoped and Al-doped ZnO nanoparticles by combustion method. ZnO nanoparticles are synthesised using zinc nitrate precursor, Aluminium nitrate as dopant and Terminalia catappa seed extract as fuel. Effect of Al (0, 1,2 and 3%) doping on microstructural, optical, thermal and electrical properties of ZnO nanoparticles are investigated. The green synthesised doped and undoped ZnO nanoparticles exhibit hexagonal wruzite structure with high crystallinity. The FTIR spectrum reaffirms the formation of Zn-O bonding structure at 454.28 cm-1 The optical band gap is found to be 3.63, 3.53, 3.22 and 3.19 eV for 0, 1,2 and 3% of Al doped ZnO nanoparticles respectively. AC conductivity of ZnO nanoparticles is found to be increased with 2% of Al doped ZnO nanoparticles. Result shows an improved structural, optical and electrical performance for 2% Al doped ZnO nanoparticles and hence these nanoparticles are suitable material for sensors, organic light emitting diodes and liquid crystal displays. [ABSTRACT FROM AUTHOR]

Numerous x-ray diagnostics at the Z facility, time-resolved and time-integrated, would benefit from a local calibrated x-ray source. For many years, Z has used low-power Manson x-ray sources to provide some characterization information for components of Z diagnostics below 30 keV. More recently, we have acquired TruFocus x-ray sources, which operate at voltages up to 100 kV depending on the anode material and model. These DC sources have demonstrated good stability and repeatability. Absolute calibrations of either sources or detectors usually involve another calibrated detector from another source, which has not been readily available locally. Therefore, we have adopted the strategy of characterizing a sensitive semiconductor diode detector by controlling or inferring the active volume. This characterized detector is then used to scale the Manson x-ray spectral shape as measured by an Amptek energy-resolving detector. The result agrees well with the modeled source spectrum. We can apply this technique to the TruFocus as well. [ABSTRACT FROM AUTHOR]

Chlorophyll has long been used as a natural indicator of plant health and photosynthetic efficiency. Laser-induced fluorescence (LIF) is an emerging technique for understanding broad spectrum organic processes and has more recently been used to monitor chlorophyll response in plants. Previous work has focused on developing a LIF technique for imaging moss mats to identify metal contamination with the current focus shifting toward application to moss fronds and aiding sample collection for chemical analysis. Two laser systems (CoCoBi a Nd:YGa pulsed laser system and Chl-SL with two blue continuous semiconductor diodes) were used to collect images of moss fronds exposed to increasing levels of Cu (1, 10, and 100 nmol/cm2) using a CMOS camera. The best methods for the preprocessing of images were conducted before the analysis of fluorescence signatures were compared to a control. The Chl-SL system performed better than the CoCoBi, with dynamic time warping (DTW) proving the most effective for image analysis. Manual thresholding to remove lower decimal code values improved the data distributions and proved whether using one or two fronds in an image was more advantageous. A higher DTW difference from the control correlated to lower chlorophyll a/b ratios and a higher metal content, indicating that LIF, with the aid of image processing, can be an effective technique for identifying Cu contamination shortly after an event. [ABSTRACT FROM AUTHOR]

Herein, we report the extraction of natural pigment curcumin from curcuma longa and their linear and third-order nonlinear optical (NLO) characteristics. The characterization techniques viz., UV–Visible absorption, FT-IR, Micro Raman and Gas Chromatography Mass Spectrum (GC–MS) are used to study the spectral characteristics of curcumin. Third-order NLO features of curcumin are studied using Z‒scan technique with a semiconductor diode laser working at 405 nm wavelength. The natural pigment exhibits negative nonlinear index of refraction resulting from self-defocusing and positive coefficient of absorption is the consequence of reverse saturable absorption (RSA). The order of nonlinear index of refraction (n2) and nonlinear coefficient of absorption (β) is measured to be 10−7 cm2/W and 10−2 cm/W, respectively. Third-order NLO susceptibility (χ(3)) and second-order hyperpolarizability (γ) of curcumin is measured to be 2.73 × 10‒7 esu and 1.67 × 10‒31 esu, respectively. A low optical limiting (OL) threshold of 0.71 mW is observed in the extracted pigment. The experimental results are supplemented by quantum mechanical calculations of the NLO parameters. The overall result finding is that curcumin extracted from curcuma longa has the potential to be novel optical candidates for photonics and optoelectronics applications. [ABSTRACT FROM AUTHOR]

Down‐conversion (DC) is a phenomenon that can enable the observation of photoluminescent quantum yield (PLQY) values exceeding 100%. A comprehensive study of the DC properties of BaF2–based single crystals with different Er3+ doping levels (1–25 mol.%) is presented. The samples exhibit a PLQY of 110% in the 1550–1650 nm under 405 nm excitation. This remarkable PLQY is attributed to a cross‐relaxation process within the energy levels of Er3+. Furthermore, when considering all emitted photons in the 1000–1650 nm range, the PLQY reaches 153% for a sample doped with 5 mol.% of Er3+. By integrating the emission of this single crystal with a Ge diode, serving as an example of a photovoltaic device sensitive to short‐wave infrared light, a significant enhancement in short‐circuit current is demonstrated. In a broader context, the presented material holds promise for improving the spectral response of low‐bandgap photovoltaic devices. [ABSTRACT FROM AUTHOR]

Semiconductor laser diodes (LDs), with merits of little volume, lightweight, low power consumption, ease of modulation, and high data rates, are great candidates for space laser communications. However, operating in a radiation environment can result in various damages to LDs. Hence, the growing focus on satellite laser communications necessitates LDs with improved radiation hardness. This review covers the efforts made in investigating the radiation effects on LDs induced by various types of radiation, including neutrons, γ-rays, protons, electrons, and other radiation particles. The conditions of radiation experiments and the behaviors and mechanisms of the degradation of LD material and device performance after being radiated are surveyed and discussed. It has been revealed that quantum dot (QD) LDs typically exhibit superior radiation tolerance compared to quantum well LDs or LDs with bulk active layers due to the enhanced confinement of carriers and reduced active areas in QD LDs, indicating significant potential for space applications. Furthermore, current challenges and issues in this field are discussed and addressed, providing a perspective and outlook for further research. Our review aims to guide the development of suitable light sources for future space laser communications, fostering high-performance satellite communications networks. [ABSTRACT FROM AUTHOR]

Recent optoelectronics domain studies concluded the increased need to provide improved, stable, and efficient designs to operate high-power NIR (Near-infrared) laser diodes. The existing current regulators provide either stability or high efficiency, with the actual studied design representing a solution providing both advantages in a complex constant current driver. Therefore, this study covers the LTI (Linear Time-Invariant) analysis of a cascade feedback loop current regulator, aiming to achieve a constant current through a high transconductance load. Furthermore, this analysis also refers to such transconductance loads as NIR laser diode bars, having their emission spectrum closely matching one major absorption band of Nd:YAG (Neodymium-dopped Yttrium Aluminum Garnet) solid-state lasers, potentially providing an increased-stability solution to high power, continuous wave side-pumped applications, as well as various DPSS (Diode-Pumped Solid-State) laser prototypes. This design is a suitable solution for an infinite transconductance load, allowing the indefinite power increase in either direct diode or pumped laser applications while maintaining adequate stability. However, as it will be covered, multiple constraints occur for this hardware design. [ABSTRACT FROM AUTHOR]

Increasing the internal light extraction efficiency of organic light‐emitting diodes (OLEDs) is key to improving their performance for solid‐state lighting applications; however, it is challenging to do this in a way that is compatible with high volume manufacturing. Here, it is shown that the outcoupling efficiency of OLEDs can be improved by diluting their hole transport layer (HTL) with the low refractive index material trifluoropropyl oligomeric silsesquioxane (F‐POSS). Specifically, co‐evaporating 40 vol.% F‐POSS in the HTL of single and multi‐stack phosphorescent OLEDs decreases its refractive index by Δn ≈ 0.2, which in turn yields a ≈12% increase in their outcoupling efficiency with no impact on electrical performance or operational lifetime. This result is significant because F‐POSS is a small molecule that sublimes cleanly, does not aggregate, and is compatible with state‐of‐the‐art HTL materials, making it a realistic path to increase light extraction in commercial OLEDs manufactured on existing production lines. [ABSTRACT FROM AUTHOR]

Lead-free halide double perovskites are considered as one of the most promising materials in optoelectronic devices, such as solar cells, photodetectors, and light-emitting diodes (LEDs), due to their environmental friendliness and chemical stability. However, the extremely low photoluminescence quantum yield (PLQY) of self-trapped excitons (STEs) emission from lead-free halide double perovskites impedes their applications. Herein, Sb3+ ions were doped into rare-earth-based double perovskite Cs2NaScCl6 single crystals (SCs), resulting in a large enhancement of PLQY from 12.57% to 87.37%. Moreover, by co-doping Sb3+ and Ho3+ into Cs2NaScCl6 SCs, the emission color can be tuned from blue to red, due to an efficient energy transfer from STEs to Ho3+ ions. Finally, the synthesized sample was used in multicolor LED, which exhibited excellent stability and optical properties. This work not only provides a new strategy for improving the optical properties of Cs2NaScCl6 SCs, but also suggests its potential application in multicolor LEDs. [ABSTRACT FROM AUTHOR]

Ultrawide bandgap heterojunction p–n diodes with polarization-induced AlGaN p-type layers are demonstrated using plasma-assisted molecular beam epitaxy on bulk AlN substrates. Current–voltage characteristics show a turn-on voltage of V bi ≈ 5.5 V, a minimum room temperature ideality factor of η ≈ 1.63 , and more than 12 orders of current modulation at room temperature. A stable current operation of the ultrawide bandgap semiconductor diode is measured up to a temperature of 300 °C. The one-sided n+–p heterojunction diode design enables a direct measurement of the spatial distribution of polarization-induced mobile hole density in the graded AlGaN layer from the capacitance–voltage profile. The measured average mobile hole density is p ∼ 5.7 × 10 17 cm−3, in close agreement with what is theoretically expected from distributed polarization doping. Light emission peaked at 260 nm (4.78 eV) observed in electroluminescence corresponds to interband radiative recombination in the n+ AlGaN layer. A much weaker deep-level emission band observed at 3.4 eV is attributed to cation-vacancy and silicon complexes in the heavily Si-doped AlGaN layer. These results demonstrate that distributed polarization doping enables ultrawide bandgap semiconductor heterojunction p–n diodes that have wide applications ranging from power electronics to deep-ultraviolet photonics. These devices can operate at high temperatures and in harsh environments. [ABSTRACT FROM AUTHOR]

Rectenna is the key component in radio-frequency circuits for receiving and converting electromagnetic waves into direct current. However, it is very challenging for the conventional semiconductor diode switches to rectify high-frequency signals for 6G telecommunication (>100 GHz), medical detection (>THz), and rectenna solar cells (optical frequencies). Such a major challenge can be resolved by replacing the conventional semiconductor diodes with tunneling diodes as the rectenna switches. In this work, metal–insulator–metal (MIM) tunneling diodes based on 2D insulating materials were designed, and their performance was evaluated using a comprehensive simulation approach which includes a density-function theory simulation of 2D insulator materials, the modeling of the electrical characteristics of tunneling diodes, and circuit simulation for rectifiers. It is found that novel 2D insulators such as monolayer TiO2 can be obtained by oxidizing sulfur-metal layered materials. The MIM diodes based on such insulators exhibit fast tunneling and excellent current rectifying properties. Such tunneling diodes effectively convert the received high-frequency electromagnetic waves into direct current. [ABSTRACT FROM AUTHOR]

Photonic crystals (PCs) can greatly enhance the optoelectronic performance of light‐emitting diodes (LEDs) due to their distinctive color, photonic band gap, etc. Therefore, many scholars have conducted extensive research based on the high light extraction efficiency, good monochromaticity, and other excellent optoelectronic properties of PC LEDs. This review discusses the main principles of photonic crystals to improve the optoelectronic performance of LEDs and summarizes 12 structural applications of photonic crystal LEDs, such as PC slabs, Bragg grating, backside reflectors, surface PC, embedded PC, dual PC, PC beads, CPC, PC thin films, LIPC, defective PC, and composite architectures with other materials that boost LED optoelectronic qualities. In summary, it is found that photonic crystals can not only greatly improve the light extraction efficiency of LEDs but also improve other optoelectronic properties such as luminescent color and directional radiation angle, and reduce the manufacturing cost of LEDs. Photonic crystal LEDs are expected to be a strong candidate for future lighting technology. Finally, the prospects and challenges of PC LEDs are summarized. [ABSTRACT FROM AUTHOR]

The modulation bandwidth in the direct modulation of a laser diode is limited by relaxation oscillation. To achieve an even higher frequency response, photon–photon resonance has been investigated to extend this modulation bandwidth. Thus far, several reports have demonstrated a higher modulation performance being achieved when utilizing PPR; however, to our knowledge, the PPR control scheme has not been comprehensively discussed. In this paper, we discuss the theory of PPR in regard to the PPR frequency, intensity, and width control scheme. We propose to utilize waveguide configuration, specifically an active multimode interferometer, for optimization. The simulation results offer an approximately 8 GHz improvement in the frequency response. [ABSTRACT FROM AUTHOR]

Multi-wavelength visible light emitters play a crucial role in current solid-state lighting. Although they can be realized by combining semiconductor light-emitting diodes (LEDs) and phosphors or by assembling multiple LED chips with different wavelengths, these design approaches suffer from phosphor-related issues or complex assembly processes. These challenges are significant drawbacks for emerging applications such as visible light communication and micro-LED displays. Herein we present a platform for tailored emission wavelength integration on a single chip utilizing epitaxial growth on flexibly-designed three-dimensional topographies. This approach spontaneously arranges the local emission wavelengths of InGaN-based LED structures through the local In composition variations. As a result, we demonstrate monolithic integration of three different emission colors (violet, blue, and green) on a single chip. Furthermore, we achieve flexible spectral control via independent electrical control of each component. Our integration scheme opens the possibility for tailored spectral control in an arbitrary spectral range through monolithic multi-wavelength LEDs. [ABSTRACT FROM AUTHOR]

In this work, we report on the fabrication, characterization and the third-order nonlinear optical (NLO) properties of basic blue 7 (BB 7) dye‒doped polyvinyl alcohol (PVA) polymer thin films. The absorption spectra of BB 7 dye‒PVA films were measured by UV‒visible absorption studies. The functional groups of BB 7‒PVA films have been identified by FT‒IR spectroscopic analysis. The surface morphology was examined by AFM and SEM analysis which shows that the BB 7 dye‒doped PVA films have a homogenous and smooth surface. The nonlinear absorption and refraction of BB 7‒PVA films were respectively explored by open aperture and closed aperture Z‒scan technique using a 5 mW semiconductor diode laser of 635 nm wavelengths. The BB 7‒PVA films exhibit the reverse saturable absorption (RSA) and self-defocusing effect and the measured third‒order nonlinear susceptibility χ(3) values of these films were found to be of the order of 10− 5 esu. The present experimental results show that BB 7‒PVA films may have potential applications in future photonic and NLO devices. [ABSTRACT FROM AUTHOR]

Antimonide semiconductor laser diodes with high brightness are ideal light sources for a variety of applications. However, the traditional structure of broad-area (BA) lasers with high-power output is normally accompanied by a multi-lobed far field profile and large lateral divergence. In this paper, we put up an on-chip microstructure for mode filtering. The excellent mode control capability is doubly confirmed by optical field simulations and complete device measurements. The optimized device shows an enhanced continuous-wave output power in exceeding of 1.3 W at room temperature, along with a reduced threshold current and increased peak power conversion efficiency. Moreover, it exhibits an ultra-stable lateral far field with a 45.6% reduction in divergence and a notable 75.5% improvement in current dependence compared with conventional BA diode lasers. The minimum divergence is as low as 5.64° for full width at half maximum definition. [ABSTRACT FROM AUTHOR]

Diodes are exposed to radiation in many operating environments, and it is important to investigate the radiation effect. In this study, the impact of X-ray radiation on the electrical properties of Mo/Cu(In0.7Ga0.3)Te2/p-Si/Al semiconductor diode was explored by I-V measurements performed before and after radiation doses between 200 and 1000 centiGray. The semiconductor diode was exposed to radiation by a linear accelerator having 6 MV X-ray. I-V measurements and the Cheung-Cheung method demonstrated the differences in series resistance, ideality factor, and barrier height. Moreover, the interface state density was obtained from I-V results. The radiation dose increased the ideality factor and decreased the barrier height. This result was thought to be due to the increase in the interface state density and the defects in the diode interface. The series resistance was increased by increasing the radiation dose due to a possible decrease in mobility and free carrier concentration. As a result of exposure to X-ray, defects occurred and due to these defects, the diode deviated from the ideal. It has been observed that the electrical properties of the diode were sensitive to X-ray radiation. The study demonstrated that the Mo/Cu(In0.7Ga0.3)Te2/p-Si/Al semiconductor diode can be implemented in X-ray radiation detection systems. [ABSTRACT FROM AUTHOR]

Biology-guided radiotherapy utilizes direct photon emissions from a positron emission tomography (PET)-avid tumor to direct planned prescription dose to the tumor. The purpose of this work is to characterize the tracked dose delivery and dosimetric performance of BgRT as a function of changes in tumor location during treatment, while contrast of tumor radioactivity relative to the background concentration is kept constant. A medical technology X1 system was utilized to create a conformal plan and deliver 1000 cGy dose in a single fraction. The experimental setup consisted of a cylindrical volumetric assembly (phantom) encapsulating a 22 mm ball target structure and a d avoidance structure. These structures were filled with F-18 fluorodeoxyglucose (FDG) and water solution with an activity concentration of 56.99 kBq/ml while the background was filled with 6.84 kBq/ml, providing a target-to-background ratio (TBR) of 8.18:1. Ashland EBT-XD monochromatic x-ray film was used as a primary diagnostic tool to characterize the tracked dose delivery and dosimetric performance of the system. A 5 cm by 10 cm piece of x-ray film was placed in between the two hemispheres of the 22 mm ball target. The patient-specific quality assurance (PSQA) is a helical assembly of 1,386 semiconductor diodes, widely used for quality assurance of radiation therapy plans. It measures the dose delivered by linear accelerator and compares it with the planned dose. The activity filled phantom was sealed and loaded in the patient-specific quality assurance (PSQA). Before proceeding to a 10 mm linear shift i n the +IEC y-axis was applied to the 22 mm ball target with respect to the to simulate a sudden patient shift. After treatment completion the x-ray film was analyzed using green channel to obtain estimation of 3%/3 mm absolute dose gamma within the planning treatment volume (PTV) and dose profiles. The irradiated x-ray film demonstrated 3%/3 mm gamma within the PTV of 95.08%. X-ray film analysis demonstrated that the delivered dose closely followed the 10 mm linear shift in the +IEC y-axis, and good dosimetric agreement was achieved between planned and delivered dose within the target. [ABSTRACT FROM AUTHOR]

Capacitive analogues of semiconductor diodes (CAPodes) present a new avenue for energy‐efficient and nature‐inspired next‐generation computing devices. Here, we disclose the generalized concept for bias‐direction‐adjustable n‐ and p‐CAPodes based on selective ion sieving. Controllable‐unidirectional ion flux is realized by blocking electrolyte ions from entering sub‐nanometer pores. The resulting CAPodes exhibit charge‐storage characteristics with a high rectification ratio (96.29 %). The enhancement of capacitance is attributed to the high surface area and porosity of an omnisorbing carbon as counter electrode. Furthermore, we demonstrate the use of an integrated device in a logic gate circuit architecture to implement logic operations ('OR', 'AND'). This work demonstrates CAPodes as a generalized concept to achieve p‐n and n‐p analogue junctions based on selective ion electrosorption, provides a comprehensive understanding and highlights applications of ion‐based diodes in ionologic architectures. [ABSTRACT FROM AUTHOR]

In this work, we design and simulate a three-dimensional (3D) SU-8 tapered edge coupler for effectively guiding light from an edge-emitting semiconductor laser diode directly to a silicon waveguide to realize a hybrid on-chip silicon light source. A series of coupling efficiencies for the commonly used top silicon thicknesses of the silicon-on-insulator wafers from 220 to 3000 nm are obtained, showing that this polymer taper can largely improve the coupling efficiency when the silicon waveguide thickness is moderate, for instance, from 41% (with no taper) to 67% for the 700 nm- thick silicon waveguide under 1 μ m gap offset and relax the lateral misalignment tolerance to above one micron by suppressing the butt refractive index contrast and the mode mismatch between the laser diode and the silicon waveguide. Wave transformation inside the tapered coupler and the input silicon waveguide has also been revealed by 3D finite-difference time-domain simulations. This 3D tapered coupler is cost effective and easily fabricated which can have wide practical applications in massive production of various silicon photonic chips based on the present complementary metal-oxide-semiconductor foundry. [ABSTRACT FROM AUTHOR]

This paper proposes a tunable antenna based on graphene for future wireless communication technology. The proposed antenna that is made by graphene/polyimide film able to tune the frequency using thermal that is exposed on it. The approach is investigated since it able to work as the other reconfiguration technique but cannot be adjustable likes diodes and liquid crystal. The antenna is fabricated into fifteen similar pieces and are separately cured at different temperature and exposure time; 250 °C, 300 °C, and 350 °C, for 20 minutes, 30 minutes, 1 hour, 2 hours, and 3 hours. The fabricated antennas are measured its S‐parameter as well as the characterisation of relative complex permittivity, sheet resistance, conductivity, surface morphology, and structure analysis. The measured results indicate that the frequency is tuned to lower within 4.1 GHz at 250 °C, 5.5 GHz at 300 °C, and 400 MHz at 350 °C. Looking into the future, even though this work is not using the same antenna, but it will lead to the proof of concept for tunable graphene antenna using thermal at fifth generation (5G) and next generation. [ABSTRACT FROM AUTHOR]

We have investigated adoption of CW blue laser diode annealing (BLDA) in manufacturing process of LTPS TFT backplane. Our experiments have shown that except crystallization annealing, BLDA can be adopted in dehydrogenation of precursor amorphous silicon film, and also can be used in the activation after ion implantation. By using BLDA dehydrogenation of H2 content as high as 20% can be implemented. In the activation, BLDA can achieve surface resistance much lower than using conventional RTA. [ABSTRACT FROM AUTHOR]

The causes of voids in the soldering layer during vacuum reflow soldering of semiconductor laser devices are investigated, as are the movement and change laws of bubbles in the voids under different reflow chamber settings. An ultrasonic scanner is used to test and experiment with a series of 1064 nm wavelength semiconductor lasers. A technique for detecting the void rate based on the wavelength difference is proposed based on the association between the device wavelength, junction temperature, and voids. The average void rate error when comparing measured and calculated values is just 1.5%, demonstrating the validity of this estimation technique for defining the void rate of the device and providing a theoretical and practical reference to analyze the void rate of the device. [ABSTRACT FROM AUTHOR]

Introduction. A semiconductor diode based on reverse current interruption is used to increase a pulse amplitude and peak power delivered on the process load. Usually, a current interrupter is located in the last stage of semiconductor-magnetic pulse generator (SMPG) and is connected in parallel to the load. Problem. Most of publications on this topic mostly concern with analysis of physical processes in the diode structure itself within its oscillating circuit, which is separated from previous SMPG’s pulse compression stages under condition of unidirectional energy transfer from the generator to the load. In this sense, the efficiency of conversion should be determined by the joint of electromagnetic interaction between non-linear compression stages, current interrupter and process load. Goal. Develop a mathematical model of nanosecond current interrupter to determine its electrical and energy characteristics as a part of high-voltage parallel circuit with magnetic pulse compression, depending on the duration and moment of current interruption, the equivalent circuit for load resistance, and to set the most optimal modes of its operation. Methodology. In this work, it is proposed to use a comprehensive approach aimed at the study of electromagnetic processes in the SMPG’s circuits with a nanosecond current interrupter, which takes into account the topology of circuit, the design parameters of saturable reactor, the magnetization curve, the equivalent load’s resistance, as well as the time parameters of power switches. Results. Analytical expressions describing the electrical and energy characteristics of the interrupter when it operating on the active load are obtained. A numerical simulation of interrupter in the SMPG’s double-loop pumping circuit is carried out, taking into account a nonlinearity of SR’s magnetization curve. Three operation modes of interrupter is described, depending on the initial moment of reverse conduction current interruption. The analysis of interrupter operation on the load with an active-capacitive component is carried out. Practical meaning. The results of research can be applied in development of high-voltage SMPG scheme with improved energy-dynamic parameters. [ABSTRACT FROM AUTHOR]

The passive multipliers based on semiconductor diodes, most frequently a Schottky type, should be driven by a certain value of input power, where the conversion losses are optimal. This means that the variation in the input power level causes the change in the output power level. A solution to this issue is the integration of an output power amplifier, which in the state of saturation provides quasi-stabilization of the output power. Practically, this approach gives an unsatisfactory performance: weak stabilization or narrow input power range. This paper comprises a concept of an active frequency multiplier with the use of one FET transistor and a special adaptive bias circuit in order to obtain a very wide input power range when the output power is stable. The principle of the operation, design guidelines, and measurement results have been presented for an example circuit of the frequency doubler. The results show the possibility to obtain up to 10 dB input power range for a 1 dB change in output power level without the use of additional amplifiers. [ABSTRACT FROM AUTHOR]

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We have investigated de‐hydrogenation of amorphous film using CW blue light semiconductor laser annealing (BLDA). Dehydrogenation of hydrogen content as high as 20% can be implemented by using BLDA. This technology can be applied for large substrate beyond G8. We will report related experiment results in this paper. [ABSTRACT FROM AUTHOR]

Suppression of speckle noise is a key issue in the development and utilization of laser display and illumination. Many approaches to reduce the speckle contrast in laser display systems have been proposed and developed. A practical high frequency laser driver circuit is designed and developed to drive green semiconductor lasers. Speckle contrast under different driving frequencies from 100Hz to 15Mhz was tested by using a speckle contrast measurement system, the speckle contrast of green laser decreased from 13.35% to 5.23%. The results show that the modulation of high frequency current of the semiconductor laser diode will destroy the coherence of the laser light and reduce the speckle contrast. The effectiveness of this method to depress speckle noise was verified. [ABSTRACT FROM AUTHOR]

A transition is made from piecemeal functions of the memristor model with threshold type switching to differentiable functions described by a single formula. Systems of equations are obtained and numerically solved for circuit sections in which the memristive device is connected in series with other discrete elements, a conventional resistor, diode, inductor, and capacitor. For the case of a serial connection of a memristor and a resistor, the calculated data are compared with the experiment. The case of series connection of a memristor and a semiconductor diode has been studied in detail. The assumptions concerning the mathematical description and physical interpretation of the influence of the electroforming process on the memristive system are presented. [ABSTRACT FROM AUTHOR]

Superconducting optoelectronic hardware has been proposed for large-scale neural computing. In this work, we expand upon the circuit and network designs previously introduced. We investigate circuits using superconducting single-photon detectors and Josephson junctions to perform signal reception, synaptic weighting, and integration. Designs are presented for synapses and neurons that perform integration of rate-coded signals as well as detect coincidence events for temporal coding. A neuron with a single integration loop can receive input from thousands of synaptic connections, and many such loops can be employed for dendritic processing. We show that a synaptic weight can be modified via a superconducting flux-storage loop inductively coupled to the current bias of the synapse. Synapses with hundreds of stable states are designed. Spike-timing-dependent plasticity can be implemented using two photons to strengthen and two photons to weaken the synaptic weight via Hebbian-type learning rules. In addition to the synaptic receiver and plasticity circuits, we describe an amplifier chain that converts the current pulse generated when a neuron reaches threshold to a voltage pulse sufficient to produce light from a semiconductor diode. This light is the signal used to communicate between neurons in the network. We analyze the performance of the elements in the amplifier chain to calculate the energy consumption per photon created. The speed of the amplification sequence allows neuronal firing up to at least 20 MHz, independent of connectivity. We consider these neurons in network configurations to investigate near-term technological potential and long-term physical limitations. By modeling the physical size of superconducting optoelectronic neurons, we calculate the area of these networks. A system with 8100 neurons and 330 430 total synapses will fit on a 1 × 1 cm 2 die. Systems of millions of neurons with hundreds of millions of synapses will fit on a 300 mm wafer. For multiwafer assemblies, communication at light speed enables a neuronal pool the size of a large data center (10 5 m 2) comprised of trillions of neurons with coherent oscillations at 1 MHz. [ABSTRACT FROM AUTHOR]

In this paper, we propose a dual manipulation on wave-front in the X band based on a reconfigurable water-based metasurface. We design and test a metasurface integrated with a saline-water substrate and PIN diodes. We showed that the wave-front reflected by the metasurface can be modulated by both the degree of salinity and the diode pattern. With these two manipulating methods, the metasurface can not only control the amplitude of the scattered beams but also the beam deflection angles, which promises a more flexible and economical way to manipulate the wave-front. We provide two diode patterns to illustrate the performance. The experimental results agree well with our simulations, further verifying our designs. Superior than the conventional reconfigurable metasurfaces, the proposed metasurface combines both water salinity and diodes, which offers more possibilities in electromagnetic (EM) wave tailoring, as well as potential applications in sensing and detection. [ABSTRACT FROM AUTHOR]

The value of a semiconductor's diode temperature determines the correct operation of this element and its useful lifetime. One of the methods for determining the die temperature of a semiconductor diode is through the use of indirect thermographic measurements. The accuracy of the thermographic temperature measurement of the diode case depends on the prevailing conditions. The temperature of the mold body (the black part of the diode case made of epoxy resin) depends on the place of measurement. The temperature of the place above the die is closer to the die temperature than the temperature of mold body fragments above the base plate. In addition, the difficulty of its thermographic temperature measurement increases when the surface whose temperature is being measured is in motion. Then, the temperature measured by thermography may not apply to the warmest point in the case where the die temperature is determined. Information about the difference between temperatures of the different parts of the mold body and the die may be important. For this reason, it was decided to check how much the temperature measurement error of the die diode changes if the temperature of the diode case is not measured at the point that is above the die. [ABSTRACT FROM AUTHOR]

This paper deals with the electron transport and heat generation in a Resonant Tunneling Diode semiconductor device. A new electrothermal Monte Carlo method is introduced. The method couples a Monte Carlo solver of the Boltzmann–Wigner transport equation with a steady-state solution of the heat diffusion equation. This methodology provides an accurate microscopic description of the spatial distribution of self-heating and its effect on the detailed nonequilibrium carrier dynamics. [ABSTRACT FROM AUTHOR]

Induction heating appliance operation is constrained by the nonlinear pot material behavior under the generated magnetic field. The equivalent load seen by the inverter varies with the intensity of the field, meaning that this variation is dependent on the mains voltage. In flexible-surface induction cooktops, this fact is combined with a high coil number and different pots to be powered simultaneously, increasing the complexity to control the transmitted power while maintaining proper mains current consumption. In this article, two noncomplementary asymmetrical modulations with in-cycle parameter variation are proposed for improved power factor correction while avoiding the need for switching frequency variation and intermodulation noise in multiload systems. The proposed strategies are analyzed and experimentally tested using a 3.6 kW multi-inverter prototype featuring five induction coils. [ABSTRACT FROM AUTHOR]

Commutation failure is one of the most important factors threatening the safety of multi-infeed high voltage direct current systems. To mitigate commutation failure, we have proposed a novel hybrid line-commutated converter by adding fully controlled devices to the conventional line-commutated converter. It aims to achieve auxiliary commutation and forced commutation with the help of fully controlled devices. Based on the novel hybrid line-commutated converter topology, the study investigates how to select suitable fully controlled devices and how to design the appropriate parameters of the devices. First, this article studied the general characteristics of reverse-blocking devices, including reverse-blocking integrated gate-commutated thyristor (RB-IGCT) and asymmetrical IGCT with diode (including fast recovery diode and standard recovery diode). Then, the novel commutation principle is carefully proposed and analyzed. The comprehensive simulation results and comparison study of the novel commutation principle are conducted. Then, according to the proposed commutation principle, the voltage and current working stress of devices are illustrated. According to these, vital features of devices, including recovery speed, on-state voltage, current conduction ability, surge current, maximum turn-off current, robustness, and volume of devices, are carefully analyzed and compared. Related experiments are conducted to present the vital characteristics of devices in the equivalent operating conditions in converters. Finally, the advantages and disadvantages of RB-IGCT and IGCT with fast recovery diode and standard recovery diode are comprehensively presented, which offers valuable reference considered in engineering applications. [ABSTRACT FROM AUTHOR]

In this article, a new efficient soft-switching synchronous rectification (SR) buck converter is proposed, which is without voltage stress increment for all switches and diodes. By introducing an auxiliary circuit to the SR buck converter,the soft-switching condition is achieved within the wide range of load power for the power semiconductor devices. The auxiliary network, which consists of capacitor, inductor, switch, and three diodes, provides a zero-voltage condition for main switch and SR switch at both the turn-on and the turn-off instant. Besides, the auxiliary inductor creates a zero-current turn-on and a zero-voltage turn-off condition for the auxiliary switch. Considering the resonance between the parasitic capacitors of the semiconductor components and the auxiliary inductor, two diodes are designed to avoid the additional voltage stress on power devices. The operating principle of this proposed converter is analyzed. A 600 W prototype is implemented to test the soft-switching operation. The advantage of the proposed converter is demonstrated by the efficiency curve over a wide range of load power against the conventional SR buck converter. [ABSTRACT FROM AUTHOR]

Due to its acceptable sensitivity to aging, on-state voltage is one of the best degradation indicators ever devised to monitor the condition of power semiconductors. The steep changes in the voltage of the semiconductors during switching have prompted the development of various circuits to extract the on-state voltage. This article proposes a simple converter-level structure for measuring the on-state voltage of every power semiconductor in a three-phase conventional inverter. As a result of its features, the proposed circuit enables the development of a hand-held portable monitoring device that can be used independently of the converter. Detailed information is given on how to design and select the components of the proposed monitoring system, along with its optimal operating conditions. In addition to the simulation results, a proof-of-concept prototype has been developed to evaluate the measurement accuracy and dynamic performance of the proposed circuit for the application of a three-phase inverter. The results confirm the overall effectiveness of the proposed topology and its comparable performance. [ABSTRACT FROM AUTHOR]

Circularly polarized (CP) electroluminescence from organic light-emitting diodes (OLEDs) has aroused considerable attention for their potential in future display and photonic technologies. The development of CP-OLEDs relies largely on chiral-emitters, which not only remain rare owing to difficulties in design and synthesis but also limit the performance of electroluminescence. When the polarization (pseudospin) degrees of freedom of a photon interact with its orbital angular momentum, photonic spin-orbit interaction (SOI) emerges such as Rashba-Dresselhaus (RD) effect. Here, we demonstrate a chiral-emitter-free microcavity CP-OLED with a high dissymmetry factor (gEL) and high luminance by embedding a thin two-dimensional organic single crystal (2D-OSC) between two silver layers which serve as two metallic mirrors forming a microcavity and meanwhile also as two electrodes in an OLED architecture. In the presence of the RD effect, the SOIs in the birefringent 2D-OSC microcavity result in a controllable spin-splitting with CP dispersions. Thanks to the high emission efficiency and high carrier mobility of the OSC, chiral-emitter-free CP-OLEDs have been demonstrated exhibiting a high gEL of 1.1 and a maximum luminance of about 60000 cd/m2, which places our device among the best performing CP-OLEDs. This strategy opens an avenue for practical applications towards on-chip microcavity CP-OLEDs. Nanoscale circularly polarized light sources are an important building block for future integrated photonics. Here the authors demonstrate circularly polarized light emission from a thin organic single crystal light-emitting diode. [ABSTRACT FROM AUTHOR]

This article concerns the indirect thermographic measurement of the junction temperature of a D00-250-10 semiconductor diode. Herein, we show how the temperature of the semiconductor junction was estimated on the basis of the heat sink temperature. We discuss the methodology of selecting the points for thermographic measurement of the heat sink temperature and the diode case. The method of thermographic measurement of the heat sink temperature and the used measurement system are described. The simulation method used to obtain the temperature of the semiconductor diode junction on the basis of the thermographic measurement of the heat sink temperature, as well as the method of determining the emissivity and convection coefficients, is presented. In order to facilitate the understanding of the discussed issues, the construction of the diode and heat sink used, the heat flow equation and the finite element method are described. As a result of the work carried out, the point where the diode casing temperature is closest to the junction temperature was indicated, as well as which fragments of the heat sink should be observed in order to correctly estimate the temperature of the semiconductor junction. The indirect measurement of the semiconductor junction temperature was carried out for different values of the power dissipated in the junction. [ABSTRACT FROM AUTHOR]

Many information technologies for numerical analysis of electrical circuit parameters have been developed. The peculiarity of these methods is their applicability not only to DC but also AC circuits, not only to linear but also nonlinear circuits. This paper introduces the special mathematical model for rectifier circuits using semiconductor diodes. In previous studies, the rectifier circuit has been modelled by differential inclusions. However, the inclusions cannot be solved by the applied programs of information technology. In this paper, the new model writing by differential equation with a special right hand side is studied to replace the classical model. The main result of this is presented in a theorem that gives the correctness of the new model. The usefulness of this study is illustrated via a concrete example. [ABSTRACT FROM AUTHOR]

We observe an optical spectrum consisting of a doublet in the output of a semiconductor laser diode with optoelectronic feedback in a dynamical regime in which a self-sustained square-wave modulation is observed, depending on injection current and feedback strength. The doublet frequency splitting is strongly correlated with the duty cycle of the square wave; both parameters as well as the relative magnitude of the peaks are observed to vary with the feedback level. A rate equation model reproduces the spectral doublets. The appearance of the doublet is attributed to active medium gain saturation and refractive index dependence on the carrier density. [ABSTRACT FROM AUTHOR]

The time-dependent charge carrier transport and recombination processes in low-mobility organic semiconductor diodes are obtained through numerical simulations using the finite element method (FEM). The application of a Lorentz force across the diode alters the charge transport process leading to the Hall effect. In this contribution, the Hall effect parameters, such as the Hall voltage and charge carrier concentration with varying magnetic fields, are computed for both Langevin and non-Langevin type recombination processes. The results indicate the charge carrier concentration within the diode for the Langevin system is about seven and fourteen times less while the maximum amount of extracted charge is nearly five and ten times less than that in the non-Langevin system of 0.01 and 0.001, respectively. The Hall voltage values obtained for the steady-state case are similar to the non-Langevin system of β β L = 0.01 . However, the values obtained for the Langevin and non-Langevin systems of β β L = 1 and 0.001 exhibit anomalies. The implications of these findings advance the understanding of the charge transport and Hall effect measurements in organic semiconductors that underpins the device's performance. [ABSTRACT FROM AUTHOR]

In this article, a family of nonisolated zero voltage switching (ZVS) bidirectional dc–dc converters (BDCs) with simple auxiliary circuit and continuous current at low voltage side source ($V_L$) is proposed. The auxiliary circuit is only composed of a single switch, a capacitor, and a small inductor which is applied to all proposed nonisolated BDCs to provide soft switching condition for all semiconductor elements. Thus, in terms of components count, the presented converters are superior to other counterpart BDCs. In addition, the continuous current at $V_L$ is maintained, while the main and auxiliary switches in both operating modes are turned on and off at ZVS. Moreover, all diodes turn off at zero current switching which mitigate the reverse recovery problem. Hence, a suitable overall efficiency is achieved in all proposed BDCs. The proposed bidirectional buck/boost converter is analyzed for both step-up and step-down operating modes in details and a 100 W converter prototype is implemented to verify the main converter features and the theoretical analysis. [ABSTRACT FROM AUTHOR]

This article proposes a three-phase six-switch switching-cell current source inverter (H6-SC-CSI) and a modified switching scheme of space vector pulsewidth modulation (SVPWM). Compared to the conventional three-phase six-switch current source inverter, the H6-SC-CSI has no open-circuit possibility, thus, the inverter reliability is greatly enhanced. In addition, the overlap-time can be minimized; hence, the output waveform quality can be considerably improved. Due to the presence of switching-cell capacitors, a conventional switching sequence of the SVPWM is modified for the inverter to operate properly. A 2.2 kW hardware prototype is built and tested to verify the effectiveness of the proposed PWM. [ABSTRACT FROM AUTHOR]

Multisource switched-capacitor multilevel inverters are proper topologies when multiple dc sources are available as renewable energy sources. However, these multilevel inverters have the main drawbacks of requiring a large number of power semiconductors and capacitors and a low boost factor to achieve a large number of voltage levels, which complicate control, reduce performance, and raise the cost. This article presents two configurations for multisource switched-capacitor multilevel inverters. First, a basic multisource switched-capacitor topology is proposed with a small number of capacitors and semiconductors that produce a zero voltage level and a large number of positive voltage levels. The input dc sources are operated in an asymmetric trinary algorithm, while the capacitors are charged/discharged in a binary algorithm using parallel/series modes (without the need for any circuit balancing). Based on the proposed basic topology, two multilevel inverter topologies are proposed, which create bipolar output voltage levels using two different circuits at the output. The first proposed topology uses a standard H-bridge inverter at the output of the basic topology, while the second topology uses an extra switched-capacitor (self-balancing) circuit. The comparison indicates that both the proposed topologies have advantages over most of the reported multisource switched-capacitor multilevel inverters, such as a small number of capacitors, a small number of power semiconductors, low voltage stress, and high boost factor. Furthermore, the proposed topologies decrease the low cost factor in comparison to other topologies. The capacitors' capacitance, power losses, and voltage ripple losses are all measured and evaluated in detail. Theoretical research is validated with the use of laboratory prototypes to validate the performance of the proposed topologies. [ABSTRACT FROM AUTHOR]

Junction temperature monitoring is the basis of high reliability operation for silicon carbide (SiC) devices, since thermal stress is the dominating aging factor. Conventional thermal sensitive electrical parameter methods have a poor monitoring performance for SiC Mosfets with low sensitivity. Thus, a high-sensitivity online junction temperature monitoring method is proposed based on the turn-on drain–source current overshoot. First, theoretical analysis is provided to clarify that the temperature difference between the body diode region and the on-state resistance region can be ignored in SiC Mosfets. It is an important basis for the proposed method, which is proven by an isothermal experiment. It is the first time to discover that the turn-on current overshoot (ΔiCm) of SiC Mosfets consists of both the reverse recovery current (iRR) and the intrinsic current overshoot (Δi0m). Next, a novel Tj monitoring strategy for SiC Mosfets is proposed based on comprehensive utilization of iRRm, Δi0m and ΔiCm. Finally, the effectiveness of the proposed method is verified by online experiments based on a dc–dc converter. The proposed method is more accurate than conventional TSEP methods with a high sensitivity of 20 mA/°C. Moreover, it still has a high monitoring performance when boundary conditions change. [ABSTRACT FROM AUTHOR]