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Indium phosphide (InP) is emerging as a viable and environmentally friendly alternative to toxic cadmium‐based quantum dots (QDs), especially in the fields of lighting and display. This is owing to similar material properties of InP to those of commercial Cd‐based QDs. Nonetheless, the surface quality of InP needs enhancement through a post‐treatment process to eliminate surface oxides, typically with hydrofluoric acid (HF). The challenge arises with smaller, such as green InP QDs, as HF easily over‐etch the InP cores, thus leading to an unpredictable size distribution and reduced production consistency. This research introduces a refined synthetic strategy that circumvents this over‐etching phenomenon and offers a more precise control over the etching process of smaller InP QDs. By applying an additional protective layer to the InP cores prior to etching and employing ammonium fluoride (NH4F) as an alternative to the conventional HF, the over‐etching incidence can be markedly mitigated. The results reveal that smaller InP/ZnSeS QDs with photoluminescence quantum yield (QY) >90% can be consistently produced, thereby proposing a more efficient and safer method for the fabrication of smaller InP QDs. [ABSTRACT FROM AUTHOR]

III‐V semiconductors are favoured photo absorber materials for solar energy conversion due to their ideal bandgap, yet their high‐cost hinders widespread adoption. Utilizing thin films of these semiconductors presents a viable way to address the cost‐related challenges. Here, a novel mechanical exfoliation technique is demonstrated, also known as controlled spalling, as a cost‐effective and facile way to obtain thin films of III‐V semiconductors. As a proof of concept, 15 μm thick InP films are successfully exfoliated from their original wafers. Thorough characterization using cathodoluminescence and photoluminescence spectroscopy confirms that the opto‐electronic properties of the exfoliated InP films remain unaffected. Utilizing these InP thin films, InP thin‐film heterojunction solar cells with efficiencies exceeding 13% are demonstrated. Additionally, InP photoanodes are fabricated by integrating NiFeOOH catalyst onto these InP thin‐film solar cells, achieving an impressive photocurrent density of 19.3 mA cm−2 at 1.23 V versus reversible hydrogen electrode, along with an applied bias photon‐to‐current efficiency of ≈4%. Overall, this study showcases the efficacy of controlled spalling in advancing economically viable and efficient III‐V semiconductor‐based solar energy conversion devices. [ABSTRACT FROM AUTHOR]

The structural properties of lattice-matched InAlAs/InP layers grown by molecular beam epitaxy have been studied using atomic force microscopy, scanning electron microscopy and micro-photoluminescence spectroscopy. The formation of the surface pits with lateral sizes in the micron range and a depth of about 2 ÷ 10 nm has been detected. The InP substrate annealing temperature and value of InAlAs alloy composition deviation from the lattice-matched InxAl1−xAs/InP case (x = 0.52) control the density of pits ranging from 5 × 105 cm−2 ÷ 108 cm−2. The pit sizes are controlled by the InAlAs layer thickness and growth temperature. The correlation between the surface pits and threading dislocations has been detected. Moreover, the InAlAs surface is characterized by composition inhomogeneity with a magnitude of 0.7% with the cluster lateral sizes and density close to these parameters for surface pits. The experimental data allow us to suggest a model where the formation of surface pits and composition clusters is caused by the influence of a local strain field in the threading dislocation core vicinity on In adatoms incorporating kinetic. [ABSTRACT FROM AUTHOR]

A significant (up to 4 times) photoluminescence enhancement of single InP/InAsP/InP nanowires transferred onto a silicon oxide‐covered silver layer on silicon substrate with a metal surface roughness level of less than 1 nm and a dielectric thickness of 5 nm has been demonstrated. This phenomenon is explained by the interaction of electron–hole pairs in the semiconductor with surface plasmon polaritons. The photoluminescence kinetics and results of modeling confirm the indicated enhancement mechanism. [ABSTRACT FROM AUTHOR]

In this study, the lasing characteristics of GaInAsP laser diodes (LDs) grown on directly bonded InP/Si substrates with a gas out channel (GOC) structure are investigated. GOC InP/Si substrates are fabricated using hydrophilic direct bonding and metal–organic vapor phase epitaxy growth methods and subsequently their surface conditions, bonding strength, and lasing performance are examined. Herein, it is observed that the introduction of a GOC substantially reduces void formation and improves the threshold current density of the LDs. In the results, it is demonstrated that the performance of the GOC InP/Si substrates is comparable to that of InP substrates, highlighting their potential for use in high‐performance optical devices. [ABSTRACT FROM AUTHOR]

In recent years, near‐infrared quantum dots (NIR QDs) have emerged as a promising candidate for biological imaging owing to their strong fluorescence penetrating into biological tissues and high imaging signal‐to‐noise ratio. Among various materials, InP QDs are environmentally friendly and have a relatively narrow bandgap of 1.35 eV, which provides a possibility for their emission wavelength to extend to the near‐infrared region. However, the strong reactivity of the precursor of phosphorus makes it challenging to synthesize NIR InP QDs, as it leads to rapid nucleation of the InP core. Herein, a method of epitaxial growth is reported to synthesize NIR InP QDs. Through high‐temperature nucleation and low‐temperature epitaxial growth, NIR InP QDs larger than 15 nm in size and with an emission wavelength of 807 nm are successfully synthesized. Furthermore, by removing InPOx defects on the surface of the core through HF etching, the quantum yield (QY) is increased from 6% to 12%. Ligand exchange successfully converted oil‐soluble ligands into water‐soluble ones, leading to excellent performance in cell imaging. The study provides a promising approach to the synthesis of desirable NIR InP QDs for use in biomedical imaging applications. [ABSTRACT FROM AUTHOR]

This paper explores the propagation loss in waveguides on directly bonded InP/Si substrates, using numerical simulations to understand the effect of voids within the waveguide structure. Using COMSOL Multiphysics, we developed a model to simulate light propagation, focusing on how void characteristics such as diameter and angle influence the propagation loss. Our findings reveal a correlation between void dimensions and the increased threshold current density in separate confinement heterostructure multiple quantum well laser diodes, thereby providing insights into optimizing waveguide design for enhanced laser performance on InP/Si substrates. This research underscores the critical role of substrate bonding quality in minimizing internal losses and improving device efficiency. [ABSTRACT FROM AUTHOR]

InP quantum dots (QDs) are regarded as the most promising star material to replace Cd-based QDs due to their excellent properties of low toxicity and tunable luminescence in the visible to infrared range. Red and green InP QDs have been shown to have excellent performance comparable to that of Cd-based QDs, but in contrast, blue InP QDs are still lagging behind. The smaller size of the core is a challenge for synthesizing high-performance blue InP QDs compared with red and green QDs. In this study, deep blue-emitting InP QDs were synthesized using a cheaper and safer phosphorus source: tris-(dimethylamino)-phosphine ((DMA)3P). A double Zn and Ga modification was applied to modulate the emission of InP QDs. A strategy for synthesizing deep blue luminescent In-(ZnGa)P QDs was proposed, and Zn-(Ac)2 was used as a precursor to react with (DMA)3P to synthesize blue InP QDs. Doping elemental Zn during nucleation inhibited the growth of the InP crystals and narrowed the lattice. Then, the Ga element further increases the material band gap by cation exchange. By introducing GaI3 into the synthesis process and utilizing the cation-exchange mechanism, deep blue emission InP QDs was realized. Tunable deep blue emission of InP QDs changed from 478 to 447 nm was achieved by this strategy. Specially, an 84% photoluminescent quantum yield is obtained for 457 nm emission QDs. This study provides clues for InP QDs to be emitted in the deep blue region, with the aim of constructing efficient deep blue QDs light-emitting diodes. [ABSTRACT FROM AUTHOR]

We demonstrate the use of laser diodes and multijunction photovoltaic power converters to efficiently deliver watts of electrical power for long-distance or cryogenic applications. Transmission through single-mode and multi-mode fibers at the wavelengths of 808 nm and 1470/1550 nm are studied. An electrical output power of ~0.1 W is obtained after a 5 km transmission through a standard single-mode SMF28 fiber fed with 0.25 W of optical power. An electrical output power of ~1 W is demonstrated after a 5 km transmission with a standard OM1 multi-mode fiber fed with ~2.5 W. Photovoltaic conversion efficiencies reaching Eff ~49% are obtained with an output voltage of ~5 V using commercial multijunction laser power converters. For low-temperature applications, an ultra-sensitive silicon photomultiplier (SiPM) is used to detect the residual light leaked from fibers as the temperature is decreased. Our study demonstrates that specific fiber types enable low-loss transmission compatible with cryogenic requirements and without light leakage triggering of the SiPM. A cryogenic power-over-fiber system at ~1470 nm is demonstrated with ~2 W of electrical power converted over a 10 m distance having a conversion efficiency of Eff > 65% at 77 K. [ABSTRACT FROM AUTHOR]

III‐V semiconductors are favoured photo absorber materials for solar energy conversion due to their ideal bandgap, yet their high‐cost hinders widespread adoption. Utilizing thin films of these semiconductors presents a viable way to address the cost‐related challenges. Here, a novel mechanical exfoliation technique is demonstrated, also known as controlled spalling, as a cost‐effective and facile way to obtain thin films of III‐V semiconductors. As a proof of concept, 15 μm thick InP films are successfully exfoliated from their original wafers. Thorough characterization using cathodoluminescence and photoluminescence spectroscopy confirms that the opto‐electronic properties of the exfoliated InP films remain unaffected. Utilizing these InP thin films, InP thin‐film heterojunction solar cells with efficiencies exceeding 13% are demonstrated. Additionally, InP photoanodes are fabricated by integrating NiFeOOH catalyst onto these InP thin‐film solar cells, achieving an impressive photocurrent density of 19.3 mA cm−2 at 1.23 V versus reversible hydrogen electrode, along with an applied bias photon‐to‐current efficiency of ≈4%. Overall, this study showcases the efficacy of controlled spalling in advancing economically viable and efficient III‐V semiconductor‐based solar energy conversion devices.

The review examines telecom electro-optic modulators made of group III–V compound semiconductor material composed of indium phosphide. The operation principles of modulators and issues of heterostructure and modulator design optimization are considered; the results of recent developments and the achieved parameters of modulators are presented. [ABSTRACT FROM AUTHOR]

The article presents the study on the comparison of gain coefficient of laser diode on silicon and InP substrate. Fabry–Perot GaInAsP bulk laser diode on InP/Si substrate is successfully obtained to study the optical gain coefficient of laser diode. The influences of temperature, threshold current comparison, and optical gain achievements between bulk InP/Si laser diode substrate and InP laser diode substrate are also analyzed using the same growth structure. A new approach is found by the research group which involves bonding of 1 μm InP semiconductor crystal and a low‐cost silicon crystal prior to epitaxial laser structure growth. With the help of metal–organic vapor‐phase epitaxy technique, GaInAsP double‐heterostructure laser is epitaxially deposited on the well‐bonded InP/Si crystal. Fabry–Perot lasing under pulsed condition is achieved, and the lasing characteristics of InP/Si substrate are compared with that of InP laser device to study the gain coefficient. [ABSTRACT FROM AUTHOR]

This paper demonstrated high-output-power and high-efficiency power amplifier (PA) monolithic microwave-integrated circuit (MMIC) at 300-GHz band (252–296 GHz) with the use of InPbased metal–oxide–semiconductor high-electron-mobility transistors (HEMTs) with composite-channel (CC) and double-side-doping (DD) techniques. The CC-DD structure obtained high output current and low channel resistance due to the improved carrier density and mobility. W-band load-pull measurement revealed the drastically improved output power density of CC-DD structure compared with that of singlechannel DD structure. The 2-stage cascaded, 4-way, and 16-way PA-MMICs were designed based on stacked common-gate transistors with current reuse topology. The cascaded PA-MMIC exhibited a poweradded efficiency (PAE) of 7.8%, and the 16-way PA-MMIC exhibited an output power of 16.9 dBm. These values are the highest among all the values reported for the 300-GHz band PA-MMICs. The 4-way PA-MMIC achieved a high output power of 13.6–14.6 dBm and high PAE of 4.8%–6.3% simultaneously at the entire 300-GHz band.

The structural properties of lattice-matched InAlAs/InP layers grown by molecular beam epitaxy have been studied using atomic force microscopy, scanning electron microscopy and micro-photoluminescence spectroscopy. The formation of the surface pits with lateral sizes in the micron range and a depth of about 2 ÷ 10 nm has been detected. The InP substrate annealing temperature and value of InAlAs alloy composition deviation from the lattice-matched InxAl1−xAs/InP case (x = 0.52) control the density of pits ranging from 5 × 105 cm−2 ÷ 108 cm−2. The pit sizes are controlled by the InAlAs layer thickness and growth temperature. The correlation between the surface pits and threading dislocations has been detected. Moreover, the InAlAs surface is characterized by composition inhomogeneity with a magnitude of 0.7% with the cluster lateral sizes and density close to these parameters for surface pits. The experimental data allow us to suggest a model where the formation of surface pits and composition clusters is caused by the influence of a local strain field in the threading dislocation core vicinity on In adatoms incorporating kinetic.

Semiconductor photocatalysis has recently emerged as a promising method for microbial inactivation. So far, quantum dots have generally been investigated as antibacterial suspension. Instead, here we demonstrate a InP/ZnS quantum dot nanoassembly film against both Gram-negative and Gram-positive bacteria. For effective operation in the solid phase, a thin layer of ZnS shell was grown on InP QD and the native long-chain ligand of stearic acid was replaced with sulfide that led to a high quantum yield of superoxide generation as 4.9%. QDs are assembled onto solid surfaces through sequential dip coating of positively charged poly-(diallyldimethylammonium chloride) and negatively charged QDs. These QD nanoassemblies demonstrate growth inhibition against Escherichia coli and multidrug-resistant Staphylococcus aureus under illumination. Interestingly, such an approach can be directly applied to irregular surfaces, as well. This study unveils the potential of the nanoengineering of QDs for antibacterial coatings. [ABSTRACT FROM AUTHOR]

Our study examined how native oxide layers, InN and InSb, affected the current-voltage and capacitance-voltage characteristics of the Au/n-InP Schottky diode at a temperature of 300 K with and without interface states, traps, and tunneling current. The simulation was carried out using the Atlas-Silvaco-Tcad device simulator. From our results, we found that the effective barrier heights were measured to be 0.474 eV, 0.544 eV, and 0.561 eV via I-V measurements and 0.675 eV, 0.817 eV, and 0.80 eV via C-V measurements. Additionally, we utilized the high-low frequency method to calculate the average density of interface state density, which was determined to be approximately 6.03 . 1011 and 3.33 . 1012 сm – 2 . eV – 1. The results indicate that a thin film of InN and InSb can effectively passivate the InP surface, as evidenced by the good performance of the passivized sample. [ABSTRACT FROM AUTHOR]

This paper uses numerical modeling to describe the design and comprehensive analysis of cost-effective MXene/n-InP Schottky barrier solar cells. The proposed design utilizes Ti3C2Tx thin film, a 2D solution-processible MXene material, as a Schottky transparent conductive electrode (TCE). The simulation results suggest that these devices can achieve power conversion efficiencies (PCEs) exceeding 20% in metal–semiconductor (MS) and metal–interlayer–semiconductor (MIS) structures. Combining the proposed structures with low-cost InP growth methods can reduce the gap between InP and other terrestrial market technologies. This is useful for specific applications that require lightweight and radiation-hard solar photovoltaics. [ABSTRACT FROM AUTHOR]

For the first time, InP layers were grown on Si substrates at a temperature of 380°C using the plasma-enhanced atomic layer deposition. According to X-ray diffraction analysis and transmission electron microscopy, the layers are microcrystalline with a grain size of 20–30 nm and a preferred orientation (111). Raman spectra exhibit clearly distinguish the LO peak at 341.9 cm–1, which is characteristic of crystalline InP. Microcrystalline InP layers grown on fused silica substrates demonstrated a high photoconductivity of 2.3 Ω–1 cm–1 under solar spectrum AM1.5G (100 mW/cm2) illumination. The study of the growth of layers of binary compounds InP and GaP in one process of plasma-enhanced atomic layer deposition demonstrated the fundamental possibility of controlling the composition of InP/GaP digital alloy. The InP/GaP digital alloys are characterized by the coalescence of the LO peaks of InP (341.9 cm–1) and GaP (365 cm–1) in the Raman spectra. Increase of GaP component in the layer leads to boarding of this feature in the Raman spectra due to a shift of the edge towards the GaP peak (402 cm–1). A study of the optical properties by transmission and reflection measurements of microcrystalline InP/GaP digital alloy layers deposited on transparent substrates demonstrated the possibility of varying the optical gap in the range of 1.3–2 eV. [ABSTRACT FROM AUTHOR]

Recent developments in long wavelength and cryogenic laser power converters have unlocked record performances in both areas. Here, devices for an optical input at ~1470 nm are studied for cryogenic applications, combining these cryogenic and long-wavelength attributes. Multijunction laser power converters are demonstrated to have a high-efficiency operation at 77 K. The photovoltaic-power-converting III-V semiconductor devices are designed with InGaAs-absorbing layers, here with 10 thin subcells (PT10), connected by transparent tunnel junctions. Unprecedented conversion efficiencies of up to 67.5% are measured at liquid nitrogen temperatures with an output power of Pmpp = 1.35 W at an average optical input intensity of ~62 W/cm2. A remarkably low bandgap voltage offset value of Woc~50 mV is obtained at an average optical input intensity of ~31 W/cm2. [ABSTRACT FROM AUTHOR]

We present vertically processed photovoltaic devices based on GaInP/InP tandem-junction III–V nanowires (NWs), contacting approximately 3 million NWs in parallel for each device. The GaInP and InP subcells as well as the connecting Esaki tunnel diode are all realized within the same NW. By processing GaInP/InP tandem-junction NW solar cells with varying compositions of the top junction GaInP material, we investigate the impact of the GaInP composition on the device performance. External quantum efficiency (EQE) measurements on devices with varying GaInP composition provide insights into the performance of the respective subcells, revealing that the GaInP subcell is current-limiting for all devices. I–V measurements under AM1.5G illumination confirm voltage addition of the subcells, resulting in an open-circuit voltage of up to 1.91 V. However, the short-circuit current density is low, ranging between 0.24 and 3.44 mA/cm2, which leads to a resulting solar conversion efficiency of up to 3.60%. Our work shows a path forward toward high-efficiency NW photovoltaics and identifies critical issues that need improvement. [ABSTRACT FROM AUTHOR]

As a kind of luminescent nanomaterial, InP quantum dots (QDs) have been regarded as one of the most potential nontoxic alternatives for cadmium-based QDs in the light-emitting devices, and much progress has been obtained recently. However, their growth kinetics remains not fully revealed yet, and the effects of the shelling process on as-synthesized InP cores have been rarely investigated. Herein, the growth kinetics of InP QDs is investigated via the convenient method of varying halide ions, and their sequential growth is proposed according to the discontinuous evolution of their first exciton absorption peaks, especially the observed typical positions, which is different from the reported continuous evolution previously and means that the specific sized InP cores appeared during the growth stage. Moreover, the impacts of ZnS are analyzed from the quantum confinement effect of ZnS on InP cores with different sizes and interfacial heterovalent bonds. The coordination between these two aspects decides the final positions of the first exciton absorption peaks of InP/ZnS QDs. Compared with the positions of the first exciton absorption peaks of bare InP QDs, insufficient confinement of the ZnS shell to small InP cores causes the red-shift, but the heterovalent bonds at the interface cause the blue-shift. Furthermore, the emissions of final InP/ZnS QDs are influenced, and the emission from 484 to 578 nm is obtained via this facile synthetic protocol. It is thought that this study can reveal the growth of InP QDs and provide guidance to design rational InP-based QDs with desired emission and high performance, contributing to the fabrication of efficient light-emitting devices. [ABSTRACT FROM AUTHOR]

Breakthroughs extending nanostructure engineering beyond what is possible with current fabrication techniques will be crucial for enabling next-generation nanotechnologies. Nanoepitaxy of strain-engineered bent nanowire heterostructures presents a promising platform for realizing the bottom-up and scalable fabrication of nanowire devices. The synthesis of these structures requires the selective asymmetric deposition of lattice-mismatched shellsa complex growth process that is not well understood. We present the nanoepitaxial growth of GaAs–InP core–shell bent nanowires and connecting nanowire pairs to form nanowire arches. The out-of-plane geometry and dual substrate connection of nanowire arches make these nanostructures highly promising for sensor-based applications. Compositional analysis of nanowire cross sections reveals the critical role of adatom diffusion in the nanoepitaxial growth process, which leads to two distinct growth regimes: indium-diffusion-limited growth and phosphorus-limited growth. The highly controllable phosphorus-limited growth mode is employed to synthesize connected nanowire pairs and quantify the role of flux shadowing on the shell growth process. Nanowires connected with shadowing are intimately fused, with the majority of shell growth forming near the interface of the two nanowires. These results provide important insight into 3D nanoepitaxy and enable possibilities for nanowire device fabrication. [ABSTRACT FROM AUTHOR]

In this study, an analysis of the optical performance of two types of distributed Bragg reflector structures based on GaAs and InP material systems was carried out. The structures were designed for maximum performance at 4 µm with their reflectivity achieving between 80 and 90% with eight pairs of constituent layers. To further enhance the performance of these structures, additional Au layers were added at the bottom of the structure with Ti precoating applied to improve the adhesivity of the Au to the semiconductor substrate. The optimal range of Ti layer thickness resulting in the improvement of the maximum reflectivity was determined to be in between 5 and 15 nm. [ABSTRACT FROM AUTHOR]

Fluorescent indium phosphide (InP) semiconductor quantum dots (QDs) are a promising low-toxicity alternative to cadmium chalcogenide QDs. It is expected that, if comparable optical characteristics are achieved, InP QDs can successfully displace Cd-containing nanocrystals from their traditional applications in optoelectronics and biomedicine. To date, unfortunately, the optical parameters of InP QDs are inferior to those of their Cd-containing counterparts, and the methods of their production require additional optimization. This paper presents the results of experiments on optimizing the synthesis of InP QDs using tris(diethylamino)phosphine as a phosphorus precursor. It has been shown that optimization of the modes of reaction mixture heating during the synthesis allows obtaining highly homogeneous InP QDs with improved optical characteristics. [ABSTRACT FROM AUTHOR]

Utilizing performed research, photoelectric converters of narrow-band radiation (λ ≈ 1.0–1.3 μm) based on InGaAsP/InP heterostructures with an epitaxial p–n junction have been developed and created. Technological regimes that apply of for creating high-quality layers of quaternary InGaAsP solid solutions isoperiodic to indium phosphide in a wide range of compositions by liquid-phase epitaxy have been determined. [ABSTRACT FROM AUTHOR]

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The vertical gradient freeze (VGF) process needs to regulate the temperature field more accurately to ensure the successful seed crystal introduction and good crystal growth condition compared to the vertical Bridgman method, such as a suitable solid–liquid interface temperature gradient. This work presents a method for regulation of the temperature field via temperature control of six heaters during VGF growth of InP crystal with numerical simulation, and shows the involution for both the melt convection and the solid–liquid interface temperature gradient. Two of the six heaters were in the heating zone, two in the gradient zone, and the others in the cooling zone. Firstly, three temperature settings for the six heaters were selected through many trial calculations to ensure the success of seed crystal introduction. Secondly, their effects on the temperature field in the crucible and the convection in the melt were investigated. The results show that the axial temperature gradient in the melt increases with an increase in the heating zone temperature or a decrease in the cooling zone temperature, of which the maximum for each simulation experiment almost always appears at the solid–liquid interface and decreases continuously with the crystal growth process. Moreover, the maximum temperature gradient in the melt for all the simulations is well below 10 K/cm due to the shouldering stage 2, which cannot improve significantly even if the heating zone temperature increases and the cooling zone temperature decreases to room temperature. The temperature setting of the heaters has no significant influence on the convection pattern in the melt, which is nearly the same for all three settings. However, the maximum velocity of the convection field increases significantly with the axial temperature gradient increase. The number of convective vortices in the melt decreases from four at the initial seeding stage to one at the end of the equal-diameter growth for every simulation, but the maximum flow velocity decreases very slowly from the shouldering stage. [ABSTRACT FROM AUTHOR]

Photovoltaic multijunction power-converting III–V semiconductor devices generate electrical power from the optical energy of laser beams. They exhibit conversion efficiencies reaching values greater than 60% and 50% for the GaAs and the InP material systems, respectively. The applications of optical wireless power transmission and power-over-fiber greatly benefit from employing such laser power converters constructed with multiple subcells; each is designed with either thin GaAs or InGaAs absorber regions. This study elucidates how the application of electric fields on thin heterostructures can create specific current–voltage characteristics due to modifications of the absorption characteristics from Franz–Keldysh perturbations and the onset of quantum-confined Stark effects. Negative differential photocurrent behavior can be observed as the reverse bias voltage is increased, until the corresponding current-clamping subcell reaches its reverse breakdown condition. The reverse voltage breakdown characteristics of the subcells were also measured to depend on the thickness of the subcell and on the optical intensity. The onset of the reverse breakdown was found to be at ~2.0–2.5 V under illumination and the thinner subcells exhibited higher levels of reverse bias currents. These effects can produce distinctive current–voltage behavior under spectrally detuned operations affecting the thinner subcells' biases, but have no significant impact on the performance and maximum power point of multijunction power converters. [ABSTRACT FROM AUTHOR]

InP‐based quantum dots (QDs) are one of the most promising heavy‐metal‐free materials for light‐emitting applications to substitute cadmium‐analogous QDs. With a bulk band gap of 1.35 eV, InP QDs can be made to emit light in the deep red and even near‐infrared region by adjusting the size. Deep‐red light‐emitting diodes (LEDs) are of great interest for promoting the growth of plants and accurate red LED displays. However, the synthesis and the fabrication of InP‐based quantum‐dot LEDs (QLEDs) emitting in the deep red region are still under development. Here, the study reports deep‐red InP/ZnSe/ZnSeS/ZnS core‐shell QDs with a photoluminescence (PL) emission peak at 680 nm and a PL quantum yield up to 95%, which is the highest among reported deep‐red QDs. Multi‐shell with a transition layer of ZnSeS is realized to decrease the lattice mismatch in the shell and increase the shell thickness, which efficiently confines charge carriers and reduces non‐radiative recombinations. In addition, the core‐shell InP QLED achieves a high luminescence of 2263 cd m−2 and an external quantum efficiency up to 6.5%. This report provides a new strategy for promoting the development of deep‐red QLEDs for next‐generation lighting and display devices. [ABSTRACT FROM AUTHOR]

Abstract The suitable direct bandgap, high carrier mobility, biologically nontoxicity, and size‐dependent physical properties of low‐dimensional indium phosphide InP (0D, 1D, and 2D) have attracted great interest from scientists. The appealing optical and electronic properties make them promising for the fabrication of state‐of‐the‐art nanoscale electronic and optoelectronic devices including photodiode, photodetector, and solar cells. This Review focuses on the recent development of low‐dimensional InP materials. The synthesis methods and growth mechanisms of high quality low‐dimensional InP are comprehensively recapped. The multifunctional applications in electronic and optoelectronic devices of low‐dimensional InP are discussed, and typical strategies to resolve the main challenges limiting the performance of low‐dimensional InP‐based application are then reviewed. Finally, a brief perspective on the challenges and opportunities of low‐dimensional InP in synthesis, electronics, and optoelectronics applications is also provided.

We have evaluated InGaAs/InP PIN (p-I-n) photodiodes failed by electrostatic discharge (ESD) with forward or reverse biasing, using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), energy dispersive x-ray spectrometry (EDX), Raman spectroscopy, and photoluminescence (PL) imaging. First, localized traces and bumps were observed on the surface of the Au electrode by SEM. Next, by cross-sectional STEM observation, a heavily damaged region including a void was observed in the p+-InP layer and an upper part of the n−-InGaAs layer just below the bump on the Au electrode. Cross-sectional EDX mapping indicated that the damaged region consists of a mixture of InP and InGaAs, i.e., InGaAsP quaternary material. In addition, poor crystal quality of the active PIN region was also revealed by Raman spectroscopy and PL imaging. Furthermore, although similar results were obtained for the ESD-failed samples with application of both forward and reverse bias, the magnitude of the ESD damage is larger in the case of forward bias as compared with the case of reverse bias. On the basis of these results, we propose a possible ESD failure mechanism that is associated with significant Joule heating in the p+-InP layer and the upper part of the n−-InGaAs layer due to the local concentration of a large current. [ABSTRACT FROM AUTHOR]

Stable and reliable optical power converting devices are obtained using vertical multi-junction laser power converters. They are based on the GaAs and the InP material systems and are used for power-over-fiber or power-beaming applications. This study demonstrates that, in addition to providing the overall best conversion efficiencies with output voltages ideal for various applications, these semiconductor photovoltaic devices are very tolerant to beam non-uniformity, partial illumination, or beam displacement variations. Examples are given with two tight beams, each covering as little as ~7% of the cell area. An optical input power of 10 W was converted with still an efficiency of Eff ~59.4%. For an input power of 20 W, the illuminated area was set to ~22% without significantly affecting the conversion efficiency of Eff ~60%. Remarkably, for a beam diameter at ~65% of the chip length (i.e., covering ~35% of the chip area), a converted power of 29.5 W was obtained using a 12-junction GaAs device with a conversion efficiency of 61%. For a 10 junction InP-based device, an efficiency of Eff = 51.1% was obtained at an output voltage reaching as high as Voc = 5.954 V for an average optical intensity of 69 W/cm2 and an illumination area of ~57%. [ABSTRACT FROM AUTHOR]

III-V compound semiconductors are widely used for electronic and optoelectronic applications. However, interfacing III-Vs with other materials has been fundamentally limited by the high growth temperatures and lattice-match requirements of traditional deposition processes. Recently, we developed the templated liquid-phase (TLP) crystal growth method for enabling direct growth of shape-controlled single-crystal III-Vs on amorphous substrates. Although in theory, the lowest temperature for TLP growth is that of the melting point of the group III metal (e.g., 156.6 °C for indium), previous experiments required a minimum growth temperature of 500 °C, thus being incompatible with many application-specific substrates. Here, we demonstrate low-temperature TLP (LT-TLP) growth of single-crystalline InP patterns at substrate temperatures down to 220 °C by first activating the precursor, thus enabling the direct growth of InP even on low thermal budget substrates such as plastics and indium-tin-oxide (ITO)-coated glass. Importantly, the material exhibits high electron mobilities and good optoelectronic properties as demonstrated by the fabrication of high-performance transistors and light-emitting devices. Furthermore, this work may enable integration of III-Vs with silicon complementary metal-oxide-semiconductor (CMOS) processing for monolithic 3D integrated circuits and/or back-end electronics.

We present multi-parameter optimization of a shallow ridge InP-based traveling wave Mach-Zehnder modulator (MZM) for ultra-wide modulation bandwidth by velocity and impedance matching and microwave attenuation minimization. Relationship between MZM microwave loss and p-cladding layer doping profile is quantitatively analyzed and incorporated in device optimization. We propose a systematic analysis methodology allowing the full optimization of an InP shallow ridge MZM capable of 200 Gb/s PAM4 operation, compatible with high-volume low-cost manufacturing. Our design is expected to achieve 4.3 V half-wave voltage and 81 GHz 3-dB bandwidth with simplified fabrication process and improved long-term reliability.

The analysis, design, and measurement of two Indium Phosphide (InP) heterojunction bipolar transistor (HBT) power amplifier (PA) designs are presented at G-band with record efficiency. A pseudo-differential common-base (CB) stage with neutralization capacitors and low-loss coupled-line balun (CLB) improve the gain and reduce matching loss. A single-stage design achieves 8.3 to 12.7-dBm output power and 7.7 to 17.3% power-added efficiency (PAE) over 180 to 220 GHz. The use of compact baluns allows the design to occupy only 0.011mm2 with power density of 1.69 W/mm2. A 3-stage, 4-way power-combined PA delivers 16.6 to 19.7-dBm output power and 6.5 to 13% PAE over 185 to 210 GHz.

The formation of ice in clouds is an important process in mixed-phase clouds, and the radiative properties and dynamical developments of clouds strongly depend on their partitioning between liquid and ice phases. In this study, we investigate the sensitivities of the cloud phase to ice-nucleating particle (INP) concentration and thermodynamics. Experiments are conducted using the ICOsahedral Nonhydrostatic model (ICON) at the convection-permitting resolution of about 1.2 km on a domain covering significant parts of central Europe, and are compared to two different retrieval products based on SEVIRI measurements. We select a day with several isolated deep convective clouds, reaching a homogeneous freezing temperature at the cloud top. The simulated cloud liquid pixel number fractions are found to decrease with increasing INP concentration both within clouds and at the cloud top. The decrease in cloud liquid pixel number fraction is not monotonic but is stronger high INP cases. Cloud-top glaciation temperatures shift toward warmer temperatures with increasing INP concentration by as much as 8 °C. Moreover, the impact of INP concentration on cloud phase partitioning is more pronounced at the cloud top than within the cloud. Moreover, initial and lateral boundary temperature fields are perturbed with increasing and decreasing temperature increments from 0 to +/-3K and +/-5K between 3 and 12 km. Perturbing the initial thermodynamic state is also found to affect the cloud phase distribution systematically. However, the simulated cloud-top liquid number fraction, diagnosed using radiative transfer simulations as input to a satellite forward operator and two different satellite remote sensing retrieval algorithms, deviates from one of the satellite products regardless of perturbations in the INP concentration or the initial thermodynamic state for warmer sub-zero temperatures, while agreeing with the other retrieval scheme much better, in particular for the high INP and high convective available potential energy (CAPE) scenarios. Perturbing the initial thermodynamic state, which artificially increases the instability of the mid- and upper-troposphere, brings the simulated cloud-top liquid number fraction closer to the satellite observations, especially in the warmer mixed phase temperature range. [ABSTRACT FROM AUTHOR]

Surfaces of InP substrates with different crystallographic orientations are investigated when facing HCl solutions. The immersion of InP(100) in HCl solutions with a wide concentrations range showed that the frontier between deoxidation and dissolution is around 6 m, with a morphological destructuration. However, no chemical evolutions are noticed even at high concentrations. Similar observations were performed with other crystallographic orientations (polycrystalline and InP(111) substrates), with topographic surface modifications but no chemical ones. [ABSTRACT FROM AUTHOR]

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Balanced charge injection into the emissive layer is a prerequisite for achieving highly efficient quantum dot light‐emitting diodes (QLEDs). The similar energy distribution of charge transport layers and indium phosphide (InP) quantum dots (QDs) facilitates excess electron injection to the InP QD layer. In this study, magnesium‐doped ZnO nanoparticles (ZMO NPs) are modified to suppress the electron injection to the InP QD layer. Particularly, hydroxyl groups are effectively replaced by electrically stable states through the passivation of ZMO NPs, retarding electron injection through the ZMO NP layer. The modified ZMO‐NP‐based InP QLEDs exhibit a maximum external quantum efficiency of 9.6% with a substantially enhanced operational lifetime compared with that of devices made with unmodified ZMO NPs. [ABSTRACT FROM AUTHOR]

Recently, nanowire detectors have been attracting increasing interest thanks to their advantages of high resolution and gain. The potential of using nanowire detectors is investigated in this work by developing a physically based model for Indium Phosphide (InP) phototransistor as well as by performing TCAD simulations. The model is based on solving the basic semiconductor equations for bipolar transistors and considering the effects of charge distribution on the bulk and on the surface. The developed model also takes into consideration the impact of surface traps, which are induced by photogenerated carriers situated at the surface of the nanowire. Further, photogating phenomena and photodoping are also included. Moreover, displacement damage (DD) is also investigated; an issue arises when the detector is exposed to repeated doses. The presented analytical model can predict the current produced from the incident X-ray beam at various energies. The calculation of the gain of the presented nanowire carefully considers the different governing effects at several values of energies as well as biasing voltage and doping. The proposed model is built in MATLAB, and the validity check of the model results is achieved using SILVACO TCAD device simulation. Comparisons between the proposed model results and SILVACO TCAD device simulation are provided and show good agreement. [ABSTRACT FROM AUTHOR]

Two three-dimensional reanalysis datasets of atmospheric composition, the Copernicus Atmosphere Monitoring Service reanalysis (CAMSRA) and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), are analyzed for the years 2003–2018 with respect to dust transport into the Arctic. The reanalyses agree on that the largest mass transport of dust into the Arctic occurs across western Russia during spring and early summer, but substantial transport events occasionally also occur across other geographical areas during all seasons. In many aspects, however, the reanalyses show considerable differences: the mass transport in MERRA-2 is substantially larger, more spread out, and occurs at higher altitudes than in CAMSRA, while the transport in CAMSRA is to a higher degree focused to well-defined events in space and time; the integrated mass transport of the 10 most intense 36-hour dust events in CAMSRA constitutes 6 % of the total integrated dust transport 2003–2018, whereas the corresponding value for MERRA-2 is only 1 %. Furthermore, we compare the reanalyses with surface measurements of dust in the Arctic and dust extinction retrievals from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) satellite data. This comparison indicates that CAMSRA underestimates the dust transport into the Arctic and that MERRA-2 likely overestimates it. The discrepancy between CAMSRA and MERRA-2 can partially be explained by the assimilation process where too little dust is assimilated in CAMSRA while in MERRA-2, the assimilation process increases the dust concentration in remote areas. Despite the profound differences between the reanalyses regarding dust transport into the Arctic, this study still brings new insights into the spatio-temporal distribution of the transport. We estimate the annual dust transport into the Arctic to be within the range 1.5–31 Tg, where the comparison with observations indicates that the lower end of the interval is less likely.

This paper uses numerical modeling to describe the design and comprehensive analysis of cost-effective MXene/n-InP Schottky barrier solar cells. The proposed design utilizes Ti3C2Tx thin film, a 2D solution-processible MXene material, as a Schottky transparent conductive electrode (TCE). The simulation results suggest that these devices can achieve power conversion efficiencies (PCEs) exceeding 20% in metal–semiconductor (MS) and metal–interlayer–semiconductor (MIS) structures. Combining the proposed structures with low-cost InP growth methods can reduce the gap between InP and other terrestrial market technologies. This is useful for specific applications that require lightweight and radiation-hard solar photovoltaics.

Hot carrier solar cells are a concept of photovoltaic devices, which offers the opportunity to harvest solar energy beyond the Shockley-Queisser limit. Unlike conventional photovoltaic devices, hot carrier solar cells convert excess kinetic energy into useful electrical power rather than losing it through thermalisation mechanisms. To extract the carriers while they are still “hot”, efficient energy-selective contacts must be developed. In previous studies, the presence of the hot carrier population in a p-i-n solar cell based on a single InGaAsP quantum well on InP substrate at room temperature has been demonstrated by means of complementary optical and electrical measurements, leading to an operating condition for this device beyond the limit for classical device operation. This result allows to design a new generation of devices to increase the hot carrier conversion contribution. In this work, we study InGaAs/AlInAs type II heterojunction as a selective contact for a future hot carrier solar cell device epitaxially grown on (001) oriented InP substrate. Two p-i-n solar cells have been grown by molecular beam epitaxy on InP. The absorber is a 50 nm-thick InGaAs layer surrounded by AlInAs barriers, all lattice-matched to InP. Two architectures are compared, the first with two symmetrical AlInAs barriers and the second with a single InGaAs quantum well in the center of the n-side barrier to allow electron tunneling across the barrier. Electrical characteristics under laser illumination with two different wavelengths have been measured to investigate the effect of the selective contact compared to the barrier. This preliminary study of InGaAs/AlInAs-based selective contacts show that such III–V combination is adapted for a future hot carrier solar cell in the InP technology.

In this paper, electronic and structural properties such as lattice constant, energy band structure, and density of states of InP in bulk and nanowire are calculated. The calculations have been performed using the Pseudopotential method in the framework of density functional theory (DFT) with local density approximation (LDA), and generalized gradient approximation (GGA) by Quantum Espresso package. The results show a direct bandgap of 1.4 eV at the Γ point in the Brillouin zone and have not cut the Fermi level, with a good agreement with the available experimental results. Also, band structure in nanowires of about 1.49 eV was calculated, which shows an increased bulk state. The calculated results show good agreement with the available experimental results.

Abnormalities in climate in recent years have been attributed to climate change. In particular, an increase in the frequency of droughts has started to influence the way we live. There is an urgent need to study and monitor droughts to prevent severe damage. Drought monitoring research is conducted using the meteorological drought index, a compilation of weather data. Although weather data are highly dependent on climatic zones, existing studies have not considered the drought index by climatic zones. This study aims to identify the spatial and climatic distribution of meteorological drought index studies and provide a well-matched combination of the drought index and climatic classification through a meta-analytic review. Data were used in the form of research papers covering the Palmer Drought Severity Index (PDSI), Standardized Precipitation Index (SPI), and Standardized Precipitation Evapotranspiration Index (SPEI) published from 2011 to 2021. The trends showed that SPEI has become a leading index for the study of drought monitoring among the three drought indices since 2015. Additionally, Asia was the focus of much of this drought research due to climate events in China. Each continent and climate classification was assigned to a different dominant drought index. For example, PDSI was commonly used in North America and continental climates, SPI in Africa, Europe, South America, and tropical and dry climates, and SPEI in Asia and temperate climates. This evaluates countries, in which drought monitoring studies are rare, using a meteorological index based on the same climatic zones. Monitoring and predicting drought patterns would improve the basic needs of humankind. [ABSTRACT FROM AUTHOR]