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The epitaxial growth of AlInGaAs alloys on InP allows the manufacture of semiconductor lasers that emit in the wavelength range between 1200 and 1600 nm in which the optical telecommunication bands lie. These alloys are particularly well suited for manufacturing lasers intended for operation at higher temperatures. A model relating the metalorganic vapor phase epitaxy (MOVPE) growth settings for AlInGaAs on InP to the resultant bandgap energy is presented, for strained and unstrained compositions, based on a new dataset measured on epitaxial layers grown in a novel planetary epitaxy reactor, using the 12x4 inch configuration. Elemental analysis (ICP‐OES) was employed to relate the growth settings to the solid‐state composition of the resulting alloy, to ensure our model takes meaningful input. It was found that the MOVPE growth settings and the solid‐state composition as determined by ICP‐OES only showed a one‐to‐one correspondence once the right set of vapor pressure coefficients for the precursors was chosen. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]

Red and green InP quantum dots (QDs) already have been demonstrated with excellent luminescence performance closing the gap with CdSe‐based QDs. However, the performance of blue InP QDs still lags behind that of red and green QDs. For blue InP QDs synthesized by aminophosphine and zinc iodide, the inherent I– possesses weak passivation ability. By introducing Br– with a smaller ion radius and larger binding energy, the quantum yield of blue InP QDs is increased from 54% to 93%, which is the highest value reported so far. Meanwhile, the long‐chain 1‐dodecanethiol is replaced by the short‐chain 1‐octanethiol through ligand exchange to increase the carrier injection efficiency. The blue quantum dot light‐emitting diodes (QLEDs) made of these QDs showed an external quantum efficiency of 2.6%, which is notably the highest blue InP QLED reported so far. [ABSTRACT FROM AUTHOR]

Hybrid thermionic‐photovoltaics (TIPV) are solid‐state thermal‐to‐electric energy converters that rely on the non‐isothermal transport of photons and electrons through a vacuum gap. In contrast to pure thermionic converters, the absorption of photons in a photovoltaic anode produces an electrochemical potential that can be delivered as electricity, ultimately boosting the power generation capacity of the device. In this work, the proof of concept of a three‐terminal TIPV converter where thermionic and photogenerated currents are collected independently is reported. Thermionic electrons are injected in the conduction band of a semiconducting anode (n‐type InP), from where they are directly extracted. Photogenerated electrons are also extracted from the conduction band of the anode, but they are then reinjected in the valence band through an independent hole‐selective contact (p‐type InGaAs). By using a low workfunction engineered anode (BaFx/InP) and cathode (ScxOy/W) a maximum power generation capacity of 125.6 and 0.35 mW cm−2 for PV and thermionic sub‐devices, respectively, is demonstrated, operating at 1400 °C. This proof of concept paves the way for the development of efficient hybrid thermionic and photovoltaic converters for the direct conversion of heat into electricity, and subsequently contributes to finding an efficient alternative to thermoelectric generators. [ABSTRACT FROM AUTHOR]

Single‐crystal indium phosphide (InP) was irradiated by swift heavy ions (40Ar, 56Fe, 86Kr, 181Ta, and 209Bi) with different energies. The damage evolutions have been investigated by means of Raman spectroscopy and electron microscopy. Analysis of Raman intensity ratio (LO′ peak to LO peak [ILO′/ILO]) provides a new insight into the lattice quality of the irradiated samples. The defect‐activated longitudinal optical mode (LO′) appeared and then disappeared with increasing ion fluences, and it seems that the peak point of ILO′/ILO is electronic energy loss dependent. The phenomenological model suggests that the LO′ peak intensity is positively correlated with the proportion of the activated regions, where the crystals were not completely disordered, but still many defects were created. Furthermore, the TEM images showed that the tracks closely overlapped, resulting in the decrease of activated regions, which implies that there is a competitive mechanism between the generation and annealing of the defects. It also provides direct evidence that the annealing effect of the defects has occurred during the swift heavy‐ion irradiation. [ABSTRACT FROM AUTHOR]

In this work, the topographical effect of the scratching trajectory and the feed direction on the formation of lithographed lines on the (001) InP surface was investigated using an atomic force microscope (AFM) tip‐based nanomachining approach. Nanoscratching tests were carried out using the sharp face of a diamond AFM tip in contact mode. From the topographic maps obtained by AFM, several morphological and fractal parameters were obtained and analyzed. Surface morphology presented a surface smoothing for surfaces with scratches produced in [011] and [001] directions. The height parameters confirmed this behavior because scratches in [001] direction exhibited lower roughness. Moreover, this scratch direction promoted the height distribution most symmetrical and platykurtic. The other morphological parameters revealed that this direction provided a more irregular surface (smaller Smc and Sxp), peak distribution, denser and pointed, smaller portion of material in the core, less deep furrows, higher spatial frequency components, and high isotropy. Fractal parameters revealed that FRE90 has the highest spatial complexity, it is dominated by higher spatial frequencies, and has the lowest surface percolation. Furthermore, all samples exhibited high topographic uniformity. [ABSTRACT FROM AUTHOR]

This article reports a comprehensive study on the damage evolution in InP crystal irradiated by swift heavy ions (SHIs, 129Xe and 209Bi). The damage effects were investigated by means of Raman spectroscopy. An analysis of the TO and LO phonon intensities ratio (ITO/ILO) for a given geometry will yield insights into the lattice quality. A direct comparison of the experimental and theoretical results of ITO/ILO has been discussed in detail. The experimental results show that the intensity ratio ITO/ILO increases with the increased ion fluences and electron energy loss (dE/dx)e. In addition, significant red‐shifts of the LO peak were observed that indicates tensile strain was induced during the energy deposition process. Theoretical analysis suggests that defects and disorders generated in the crystals strongly contribute to the intensity ratio ITO/ILO. By TEM observation, we obtained direct evidence that the proportion of disorders and amorphization is proportional to the (dE/dx)e of incident ions, which further confirms that the ITO/ILO ratio measured by Raman spectroscopy is function of irradiation‐induced damages. Therefore, the variation in the intensity ratio ITO/ILO can be used as a nondestructive tool to evaluate the lattice damages in zincblende‐type crystals. [ABSTRACT FROM AUTHOR]

Electroluminescent QD‐EL devices based on InP and ZnTeSe quantum dots are one of the most promising future display technologies. With improvement in synthesis, we have developed high quantum yield environmental‐friendly quantum dots and through device optimization we have achieved efficiencies of 21.0% and 13.5% for red and blue QD‐ELs, respectively. In this paper, we report on the impact of the quasi‐cubic morphology of quantum dots to device efficiency performance. [ABSTRACT FROM AUTHOR]

Aerosol‐cloud interactions are an important source of uncertainty in current climate models. To understand and quantify the influence of ice‐nucleating particles in cloud glaciation, it is crucial to have a reliable estimation of the hemispheric and seasonal contrast in cloud top phase, which is believed to result from the higher dust aerosol loading in boreal spring. For this reason, we locate and quantify these contrasts by combining three different A‐Train cloud‐phase products for the period 2007–2010. These products rely on a spaceborne lidar, a lidar‐radar synergy, and a radiometer‐polarimeter synergy. We show that the cloud‐phase from the product combination is more reliable and that the estimation of the hemispheric and seasonal contrast has a lower error compared to the individual products. To quantify the contrast in cloud‐phase, we use the hemispheric difference in ice cloud frequency normalized by the liquid cloud frequency in the southern hemisphere between −42 °C and 0 °C. In the midlatitudes, from −15 to −30 °C, the hemispheric contrasts increase with decreasing temperature. At −30 °C, the hemispheric contrast varies from 29% to 39% for the individual cloud‐phase products and from 52% to 73% for the product combination. Similarly, in the northern hemisphere, we assess the seasonal contrast between spring and fall normalized by the liquid cloud frequency during fall. At −30 °C, the seasonal contrast ranges from 21% to 39% for the individual cloud‐phase products and from 54% to 75% for the product combination. Plain Language Summary: The influence of atmospheric particles on clouds is one of the main unknowns in climate predictions. Particularly, the cloud glaciation process and its dependence on desert dust and soot particles are not well‐understood. To better understand the differences in cloud glaciation between hemispheres, we counted liquid and ice cloud tops, as observed from four different satellites, during 4 years. Combining these observations, we could confirm a higher frequency of ice cloud tops during spring in the northern hemisphere. We found that the contrast between hemispheres is higher than previously thought. These results will help to improve our understanding of cloud glaciation processes, which can be valuable for future climate predictions and for understanding the impact of aerosols on radiation and precipitation. Key Points: A satellite product ensemble was used to locate and quantify the hemispheric and seasonal contrast in cloud top thermodynamic phaseAt −30 °C, half of the liquid cloud tops observed in the southern hemisphere would glaciate in the northern hemisphereThe new product ensemble is more reliable than the individual products and suggests a previous underestimation of the cloud‐phase contrasts [ABSTRACT FROM AUTHOR]

We have previously shown (Nanomaterials, 2020, 10 (9), 1858) that InPZnS/ZnSe/ZnS multishell quantum dots (QDs) with a variety of shell thicknesses can be dispersed in water using a ligand exchange reaction with mercaptocarboxylic acids. Here, we demonstrate that the concept can further be extended to a larger variety of QD core sizes while keeping the shell thickness constant. The photoluminescence quantum yield of the QDs in the aqueous phase depends on the QD size and the QDs only show a slight red‐shift upon dispersion in water. This provides access to a larger group of particles with different emission colors, which is interesting for application in e. g. biological or medical diagnostics. [ABSTRACT FROM AUTHOR]

As the concerns about using cadmium‐based quantum dots (QDs) in display are growing worldwide, InP QDs have drawn much attention in quantum dot light‐emitting diodes (QLEDs). However, pure blue InP based QLED has been rarely reported. In this work, first of all, pure blue InP/ZnS QDs with emission wavelength of 468 nm and quantum yield of 45% are synthesized. Furthermore, zinc oleate and S‐TOP are used as precursors to epitaxially grow the second ZnS shell. The residual zinc stearate reacted with S‐TOP to form ZnS shell, which increased the thickness and stability of QDs. Moreover, as the residual precursor of zinc stearate is removed, the current density increased from 13 mA cm−2 to 121 mA cm−2 at 8 V for the hole only device. External quantum efficiency increased from 0.6% of InP/ZnS QLED to 1.7% of InP/ZnS/ZnS QLED. [ABSTRACT FROM AUTHOR]

Ti/GO/n‐InP Schottky barrier diode (SBD) is obtained by growing graphene oxide (GO) film on n/InP semiconductor using easy and economical spray pyrolysis method. The effect of GO as the interfacial layer on device performance of Ti/GO/n‐InP SBD is investigated in detail. The optical absorbance spectra show that bandgap energy of the GO film is 3.57 eV. The optical transmittance value of 79.5% is in consistent with the absorbance spectra of GO film. The barrier heights (BHs) that are estimated for the Ti/GO/n‐InP SBD vary from 0.263 to 0.980 eV (I–V) and 1.328 to 1.006 eV (C–V) from the I–V and C–V measurements in the temperature range of 100–400 K. The contradiction between the BHs from the I–V and C–V characteristics is discussed. The mean BH values are found to be Φb01 = 0.98 eV (250–400 K) and Φb02 = 0.73 eV (100–250 K) from the Φb0–1/2kT plot. From the modified Richardson plots based on a Gaussian distribution of BH, Φb01 = 0.93 (250–400 K) and Φb02 = 0.69 eV (100–250 K) and A* is calculated to be 12.44 and 12.73 A cm−2 K−2, respectively. The I–V–T and C–V–T measurements demonstrate that carrier transport mechanism of Ti/GO/n‐InP is well explained by thermionic emission (TE) mechanism with a double Gaussian distribution of the Schottky barrier heights (SBHs). [ABSTRACT FROM AUTHOR]

This study reports an analysis of noise figures (NFs) in a reflection‐type microwave amplifier using resonant tunnelling diodes (RTDs). The minimum NF for the RTD amplifier based on 0.9 μm InP process technology, featuring a power gain (S21) of 10.4 dB and a dc‐power consumption of 133 μW at a centre frequency of 5.7 GHz, is measured to be 5.08 dB at a bias voltage of 0.355 V. The estimated NF characteristic based on an equation of the noise factor caused by the shot noise (FSH) and a simulation of the noise factor generated by the thermal noise (FTH) closely matches the measured NF characteristic, in the high‐gain bias range of 0.32–0.38 V and near the centre frequency. It is found that the measured NF value of 5.08 dB originates mostly from the FSH of 1.88 and the FTH of 2.02. Additionally, the effect of the RTD parameters on the achieved NF is investigated, indicating that the negative resistance (RD) magnitude had a dominant effect on the NF by changing the FTH as well as the FSH. [ABSTRACT FROM AUTHOR]

A novel InP#x02010;based metal#x02010;coated sidewall, hybrid plasmonic multimode interference (MCS#x02010;HP#x02010;MMI) power splitter has been proposed. Based on two methods of multimode interference self#x02010;imaging and finite difference time domain simulations, a 1 × 2 MCS#x02010;HP#x02010;MMI power splitter was numerically analysed and compared with an HP#x02010;MMI power splitter with the same specifications showing 70% reduction in length due to the negative Goos–Hänchen shift in the metal#x02010;coated sidewalls of the MCS#x02010;HP#x02010;MMI power splitter. The width and layer stack specifications of the device were optimised using response surface methodology to minimise the multimode interference length and maximise the optical power transmission. The total optical power transmission of 98% was achieved for an MCS#x02010;HP#x02010;MMI width and length of 662 and 190 nm, respectively, with a wavelength of 1550 nm. [ABSTRACT FROM AUTHOR]

Electroluminescent QD‐LEDs with heavy metal free InP and ZnTeSe quantum dots are one of the most promising future display technologies. Here we report improved efficiency of 19.6%, 17.6%, and 11.5% for red, green, and blue QD‐LEDs, respectively. The blue QD‐LEDs exhibit true blue emission with peak wavelength of 453 nm. [ABSTRACT FROM AUTHOR]

The ways in which marine biological activity affects climate, by modifying aerosol properties, are not completely understood, causing high uncertainties in climate predictions. In this work, in situ measurements of aerosol chemical composition, particle number size distribution, cloud condensation nuclei (CCN), and ice‐nucleating particle (INP) number concentrations are combined with high‐resolution sea surface chlorophyll‐a concentration (CHL) and back‐trajectory data to elucidate the relationship between oceanic biological activity and marine aerosol. The measurements were performed during an intensive field campaign conducted in late summer (August–September) 2015 at the Mace Head Research Station (MHD). At the short time scale (1–2 months) of the experiment, we observed a clear dependency of the main aerosol physicochemical and cloud‐relevant properties on the patterns of biological activity, in specific oceanic regions with a delayed response of about 1–3 weeks. The oceanic region comprised between 47°–57°N and 14°–30°W was identified as the main source of biogenic aerosols during the campaign, with hints of some minor influence of waters up to the Greenland coast. These spatial and temporal relationships demonstrate that the marine biota influences aerosol properties under a variety of features up to the most cloud‐relevant properties. Such dependency of aerosol properties with oceanic biological activity was previously reported over the North Atlantic Ocean only for multiyear data sets, where the correlation may be enhanced by coincident seasonalities. A better knowledge of these short time scale interactions may lead to a significant improvement in understanding the ocean‐atmosphere‐cloud system, with important impacts on climate science. Key Points: Marine aerosol composition and cloud‐relevant properties over the North Atlantic Ocean are driven by phytoplankton activity patternsThe main source region of marine biogenic aerosol reaching Mace Head was identified between 47°–57°N and 14°–30°WThe relation is observed on a short time scale (1–2 months) and occurs with a delayed response of about 1–3 weeks [ABSTRACT FROM AUTHOR]

Photonic integrated circuits (PICs) suffer from birefringence due to high‐index contrast. Polarisation handling devices improve the performance of the PICs by reducing the polarisation‐dependent dispersion and loss. Furthermore, there is a growing interest in building polarisation division multiplexed transceivers using PICs, which require polarisation management. The authors provide an overview of the recent work on developing polarisation handling devices such as polarisation beam splitters and polarisers in indium phosphide and silicon‐on‐insulator platforms for optical communications and sensing applications. These devices expand the PICs library of polarisation handling devices and can be used to design more complex circuits with advanced or new functionalities. [ABSTRACT FROM AUTHOR]

This study reports on a sub‐mW triple‐push oscillator using resonant tunnelling diodes (RTDs) operating at a frequency of 225 GHz. The triple‐push RTD oscillator is designed based on a stability test using even/odd‐mode equivalent circuit models and fabricated by using an indium phosphide monolithic microwave integrated circuit process. The fabricated IC exhibits an extremely low dc‐power consumption (PDC) of 0.5 mW with a dc‐to‐radio‐frequency efficiency of 1%. These results are attributed to both device characteristics of the RTDs with a low bias voltage of 0.4 V and a low peak current density of 0.74 mA/μm2 and an efficient triple‐push topology exploiting the strong odd symmetry of the RTD I–V curve with a wide negative differential conductance voltage span of 0.46 V. [ABSTRACT FROM AUTHOR]

Here we report the ice nucleating temperatures of marine aerosols sampled in the subarctic Atlantic Ocean during a phytoplankton bloom. Ice nucleation measurements were conducted on primary aerosol samples and phytoplankton isolated from seawater samples. Primary marine aerosol samples produced by a specialized aerosol generator (the Sea Sweep) catalyzed droplet freezing at temperatures between −33.4 °C and − 24.5 °C, with a mean freezing temperature of −28.5 °C, which was significantly warmer than the homogeneous freezing temperature of pure water in the atmosphere (−36 °C). Following a storm‐induced deep mixing event, ice nucleation activity was enhanced by two metrics: (1) the fraction of aerosols acting as ice nucleating particles (INPs) and (2) the nucleating temperatures, which were the warmest observed throughout the project. Seawater samples were collected from the ocean's surface and phytoplankton groups, including Synechococcus, picoeukaryotes, and nanoeukaryotes, were isolated into sodium chloride sheath fluid solution using a cell‐sorting flow cytometer. Marine aerosol containing Synechococcus, picoeukaryotes, and nanoeukaryotes serves as INP at temperatures significantly warmer than the homogeneous freezing temperature of pure water in the atmosphere. Samples containing whole organisms in 30 g L−1 NaCl had freezing temperatures between −33.8 and − 31.1 °C. Dilution of samples to representative atmospheric aerosol salt concentrations (as low as 3.75 g L−1 NaCl) raised freezing temperatures to as high as −22.1 °C. It follows that marine aerosols containing phytoplankton may have widespread influence on marine ice nucleation events by facilitating ice nucleation. Key Points: Isolated small phytoplankton cells, including Synechococcus, picoeukaryotes, nanoeukaryotes catalyze atmospheric ice nucleationAt seawater concentrations, salts in water droplets inhibit ice nucleation by biological componentsFollowing a storm‐driven mixing event, the mean ice‐nucleating temperature of primary aerosol rose from −28.0 ± 1.5 °C to −24.5 ± 0.9 °C [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (QDs)‐based light‐emitting diodes (QLEDs) has been actively researched due to the potential impacts to the display and lighting industry base on the unique properties of QDs itself such as size‐dependent bandgap tunability, narrow emission spectrum, and low‐cost solution‐based processing. However, the most of promising results in the past used cadmium (Cd) contained II‐VI semiconductor nanocrystals. Therefore, a considerable future task is to substitute QDs with less toxic materials. InP‐based QDs is a promising material for colour‐saturated display among the III‐V semiconductor nanocrystals and it has been already applied in conventional and inverted QLED structure. [ABSTRACT FROM AUTHOR]

The authors propose a 2 × 2 asymmetric adiabatic coupler (AAC) indium phosphide (InP) photonic integrated circuit (PIC), suitable for tunable power applications such as all‐optical data processing. The device was idealised as the key building block in Haar transform network used for image compression, allowing to perform the necessary separate addition and subtraction of incoming input signals at its output ports. The tunable behaviour of the coupler was demonstrated experimentally for addition/subtraction and splitting (with experimental coupling ratios of 77:23/14:86 and 50:50, respectively) through phase control. The use of the developed InP PIC enables a low footprint structure design together with the high‐quality active components (lasers, photodetectors and phase modulators) of Fraunhofer Gesellschaft Heinrich Hertz Institute design toolkit. The proposed study provides a full experimental characterisation of the AAC, exploring its tuning properties and enabling further usage in a plethora of applications in high processing computing and data communications. [ABSTRACT FROM AUTHOR]

This Letter reports the design, fabrication and characterisation of a new differential linear driver, fabricated in the III-V Lab 0.7- ${\rm \mu }{\rm m}$μm emitter width indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. Large-signal electrical characterisation shows 80-GBd symbol-rate four-level pulse amplitude (PAM-4) modulation conjugated with a driver output swing of 3-Vppdiff and a 0.74-W power consumption. Thus resulting in a 1.22-GBd driving efficiency, the highest in over 70-GBd drivers' state-of-the-art, at that date. Accordingly, S-parameter measurements of the standalone linear driver exhibit the highest gain-bandwidth product of 556 GHz, in that current state-of-the-art. [ABSTRACT FROM AUTHOR]

A carrier signal lock‐in experiment using a 300‐GHz integrated heterodyne circuit is presented. The circuit contains a single voltage‐controlled oscillator with a single set of quadrature mixers that are fabricated using 250‐nm InP double hetero‐junction bipolar transistor technology. An external feedback loop containing packaged baseband components such as amplifiers, a phase discriminator, and a filter is connected to the integrated circuit to form a complete receiver system. For a −25 dBm of input RF signal with 3.5‐GHz single‐tone carrier‐suppressed modulation, the receiver system responds with successful lock‐in range of 110 MHz centred around 311 GHz. [ABSTRACT FROM AUTHOR]

Indium phosphide/reduced graphene oxide (InP/rGO) composites were synthesized successfully through a facile one‐step route at 180 °C. The InP nanoparticles can be anchored uniformly on the surface of rGO nanosheets, forming a stable composite. Moreover, the size and dispersibility of InP nanoparticles can be greatly affected by the added rGO amount. The as‐prepared InP/rGO composites show better electrochemical performance than single‐component rGO nanosheets or InP nanoparticles. But, when the amount of rGO added is 5 mg, the electrochemical performance of InP/rGO composite is optimum. It delivers an initial discharge capacity of 1872 mAh g−1 and the reversible specific discharge capacity can remain at 689 mAh g−1 after 100 cycles at a current density of 100 mA g−1. Even at a current density of 500 mA g−1, the reversible specific capacity could still reach 500 mAh g−1. The enhanced electrochemical performances of as‐prepared composites might be attributed to the strong interaction between InP nanoparticles and rGO nanosheets. Stick it down: Indium phosphide/reduced graphene oxide (InP/rGO) composites are synthesized by using a one‐step route at 180 °C. The InP nanoparticles can be anchored uniformly on the surface of rGO nanosheets. By adjusting the amount of CTAB, the adhesion rate of redox graphene on the InP surface can be controlled to modify the electrochemical performance. When the current density is 50 mA g−1, the optimal sample discharge specific capacity is stable at 797 mAh g−1. [ABSTRACT FROM AUTHOR]

Abstract: In the framework of this overview, the past four decades of research activities from the Freiburg Crystallography in the field of crystal growth in microgravity (µg) environments is presented. Crystal growth from the melt and solution phases of different materials was investigated onboard various manned and unmanned µg platforms such as parabolic flights, shuttle missions, satellite missions, and sounding rocket flights. The focus of material research in Freiburg was and is still in semiconducting materials; elemental semiconductors like Si, Ge, and GeSi as well as various compound semiconductors like InP, GaAs, and CdTe. The objectives of the single experiments, the results, and their further application and utilizations are summarized in this overview. [ABSTRACT FROM AUTHOR]

We demonstrate efficient InP‐based quantum dot (QD) LEDs utilizing a crosslinkable hole transport layers (HTL). The developed HTL exhibit great solvent resistance and smooth surface roughness. The influence of QD design, HTL structure as well as the corresponding processing of these materials on device performance was investigated. [ABSTRACT FROM AUTHOR]

In this study, an area‐selective metal‐organic vapor‐phase epitaxy (MOVPE) for trench‐confined InP‐based epitaxial regrowth in‐between arrayed rectangular‐shaped device elements is reported. Test structures are fabricated to investigate the influence of MOVPE growth and other processing parameters on regrowth control, doping incorporation, and morphology. For correctly chosen crystallographic mesa orientation and mask geometry, good control of growth selectivity, layer morphology, and doping concentration can be achieved, although with an enhanced and non‐constant growth rate. This is discussed in terms of orientation‐dependent growth rate and loading effects. In addition, a selective etch and regrowth approach which allows for the processing of field‐effect transistors of significance for spatial light modulators with trench‐integrated driver electronics is successfully implemented. [ABSTRACT FROM AUTHOR]

Crystal growth on a Si substrate for the fabrication of a 1.2 µm GaInAsP laser diode is demonstrated via metal organic vapor phase epitaxy and lasing operation in the pulse regime at room temperature was successfully achieved. Direct wafer bonding at 400 °C for the InP thin film and Si substrate is conducted prior to the growth process is adopted. After the bonding process, epitaxial layers are grown for the monolithic integration of InP optical devices on the wafer‐bonded InP/Si substrate. The surface after crystal growth is quite smooth and contains less voids. The photoluminescence (PL) intensity of GaInAsP on the InP/Si substrate is almost equivalent to the PL intensity of InP substrate as a reference. After forming a metallic contact at the n‐Si and p‐InP sides, the chips are cleaved and the current density‐light output (I‐L) characteristics are measured. The I‐L characteristics show that there is a difference in the threshold current density between the InP/Si substrate and InP substrate. The increase in the threshold current density is dependent on the measurement temperature, and that for the InP/Si substrate was as low as 4 kA cm−2. [ABSTRACT FROM AUTHOR]

We explore conditions for achieving laser liftoff in epitaxially grown heterojunctions, in which single crystal thin films can be separated from their growth substrates using a selectively absorbing buried intermediate layer. Because this highly non‐linear process is subject to a variety of process instabilities, it is essential to accurately characterize the parameters resulting in liftoff. Here, we present an InP/InGaAs/InP heterojunction as a model system for such characterization. We show separation of InP thin films from single crystal InP growth substrates, wherein a ≈10 ns, Nd:YAG laser pulse selectively heats a coherently strained, buried InGaAs layer. We develop a technique to measure liftoff threshold fluences within an inhomogeneous laser spatial profile, and apply this technique to determine threshold fluences of the order 0.5 J cm−2 for our specimens. We find that the fluence at the InGaAs layer is limited by non‐linear absorption and InP surface damage at high powers, and measure the energy transmission in an InP substrate from 0 to 8 J cm−2. Characterization of the ejected thin films shows crack‐free, single crystal InP. Finally, we present evidence that the hot InGaAs initiates a liquid phase front that travels into the InP substrate during liftoff. [ABSTRACT FROM AUTHOR]

Periodic arrangement of twin planes creates a controllable polytype that can affect both the electronic and optical properties of nanowires. The approach that is most used for inducing twinning superlattice (TSL) formation in III-V nanowires is introducing impurity dopants during growth. Here, we demonstrate that controlling the growth parameters is sufficient to produce regular twinning planes in Au-catalysed InSb and InP nanowires. Our results show that TSL formation in InSb nanowires only exists in a very narrow growth window. We suggest that growth conditions induce a high concentration of In (or Sb) in the Au droplet, which plays a similar role to that of surfactant impurities such as Zn, and increases the droplet wetting angle to yield a geometry that is favorable for TSL formation. The demonstration of TSL structure in InSb and InP nanowires by controlling the input of In (or Sb) further enhances fundamental understanding of TSL formation in III-V nanowires and allows us to tune the properties of these nanowires by crystal phase engineering. [ABSTRACT FROM AUTHOR]

This study presents a new design for a single-junction InAlAs solar cell, which reduces parasitic absorption losses from the low band-gap contact layer while maintaining a functional window layer by integrating a selective etch stop. The etch stop is then removed prior to depositing an anti-reflective coating. The final cell had a 17.9% efficiency under 1-sun AM1.5 with an anti-reflective coating. Minority carrier diffusion lengths were extracted from external quantum efficiency data using physics-based device simulation software yielding 170 nm in the n-type emitter and 4.6 μm in the p-type base, which is more than four times the diffusion length previously reported for a p-type InAlAs base. This report represents significant progress towards a high-performance InAlAs top cell for a triple-junction design lattice-matched to InP. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A novel multi-junction GaP/InP/Si solar cells with improved p++AlGaAs/n++ AlGaAs tunnel junction model is designed using the Synopsys/RSoft/Solar cell utility software. The optical and electrical simulations of this cell are performed using the 2D full-wave and solar cell utility, resulting in an open circuit voltage of 3.02 V, short circuit current density of 15.942 mA/cm2, fill factor of 82.7%, and power conversion efficiency of 44.23%. Then, an optimization study of a function of variation in thickness of different layers is performed. Simulation results of the optimized structure under AM 1.5G condition showed a small improvement in the short circuit current density by 0.38%, efficiency by 0.375%, whereas the fill factor and open circuit voltage are maintained the same. The proposed multi-junction solar cell has reported the highest power conversion efficiency of 44.397% among the III-V triple junction solar cells designed already. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We prepared green and red light emitting InP/ZnSeS Quantum Dots (QDs) with remarkably high quantum efficiency (up to 90%) and the narrow spectrum width (less than 40nm). These environmentally friendly QDs are very competitive for the applications of color-saturated display compared to the previously developed Cd containing QDs. Although the III-V compound semiconductor nanomaterials are known to be sensitive to oxidizing atmosphere, synthetic process for mass production was successfully established. To complement the vulnerability of QDs to oxygen and moisture, matrix polymer and barrier layer were designed in terms of stability and cost effectiveness. The processes including the preparation of QD resin and large area coating were also well established. To improve the properties of QD film, much effort has been put for better efficiency and stability. Also, it has been suggested that the various forms of displays utilizing the benefit of the QDs would be followed in near future. [ABSTRACT FROM AUTHOR]

The low-temperature data of Hall-effect measurements on p-type InP doped with Cd, Zn, or Mg reported by Benzaquen et al., which exhibit the characteristic of nearest-neighbor hoping conduction in an impurity band, have been analyzed within the two-band model including the valence band and the impurity band. It is shown that the temperature-dependent Hall-effect data can be well fitted by assuming the hopping drift mobility expressed as μib = μib0( T0/ T)3/2exp(− T0/ T) and the hopping Hall factor expressed as Aib = ( kB T/ J)exp(− T0H/ T) on the basis of a small-polaron theory. Especially, Hall-effect sign anomaly observed at low temperature in Mg-doped InP is well reproduced by assuming a negative Hall effect for hoping conduction. The sign of the Hall coefficient for hoping conduction is discussed in connection with the overlap between the upper and the lower impurity Hubbard bands. [ABSTRACT FROM AUTHOR]

A dot-in-well structure for quantum dot (QD) growth on InP (001) vicinal substrates was introduced to increase the emission wavelength. The emission wavelength of the QDs changed from 1600 nm in conventional structures to 1850 nm in the proposed dot-in-well structure, when measured at room temperature. The emission intensity of this dot-in-well structure was the same as that of the conventional structure, implying that the dot-in-well structure did not degrade crystal quality. [ABSTRACT FROM AUTHOR]

The authors obtained very good back‐to‐back bit error rate performance in up to 80 Gbaud DP‐16QAM operation by using their coherent driver modulator of a 3‐dB electro‐optic bandwidth of over 50 GHz. To achieve high bandwidth and good signal integrity, they used double ultra‐low loop wires between the driver IC and the modulator and a differential capacitively loaded travelling‐wave RF electrode based on straight coupled coplanar waveguide with a ground‐signal–signal‐ground configuration for their InP modulator. As far as they know, this is the highest bandwidth and baud rate operation so far for the high‐bandwidth coherent driver modulator configuration. [ABSTRACT FROM AUTHOR]

In this work, the authors present two transimpedance amplifier (TIA) circuits designed for fibre optical interconnect systems. They compare a common base (CB) topology with a common emitter (CE) shunt–shunt feedback topology in terms of frequency response, power consumption, noise, and input impedance. The two TIAs are designed on a 130 nm indium phosphide double heterojunction bipolar transistor technology from Teledyne Scientific Company (TSC) with an ft/fmax of 520 GHz/1.15 THz and are measured in the frequency and time domains. They exhibit a transimpedance gain of 42 dBΩ with a 133 GHz bandwidth, the highest bandwidth reported in the literature and power consumption of 32.3 mW for the CB and 25.5 mW for the CE. Eye diagram measurements were conducted up to 64 Gbps and input referred noise density was measured at 30.2pA/Hz for the CB and 13.9pA/Hz for the CE. [ABSTRACT FROM AUTHOR]

In this Letter, the authors report on the design, optimisation and electrical measurements of a new fully integrated multiplexing selector fabricated in 0.7‐µm indium phosphide (InP) double‐heterojunction bipolar transistor technology. All parts of the circuit were optimised to obtain 200‐Gbit/s class of operation. They present electrical performances at 140 and to a record speed of 212 Gbit/s, highlighting their respective measurement challenges. The power consumption of the circuit is 0.5 and 0.8 W for a differential output amplitude of 240 and 730 mV, respectively. This selector has been successfully used as modulator driver in optical transmission experiments up to 204 Gbit/s. [ABSTRACT FROM AUTHOR]

The authors present a manufacturing cost analysis for producing thin-film indium phosphide modules by combining a novel thin-film vapor-liquid-solid (TF-VLS) growth process with a standard monolithic module platform. The example cell structure is ITO/n-TiO2/p-InP/Mo. For a benchmark scenario of 12% efficient modules, the module cost is estimated to be $0.66/W(DC) and the module cost is calculated to be around $0.36/W(DC) at a long-term potential efficiency of 24%. The manufacturing cost for the TF-VLS growth portion is estimated to be ~$23/m2, a significant reduction compared with traditional metalorganic chemical vapor deposition. The analysis here suggests the TF-VLS growth mode could enable lower-cost, high-efficiency III-V photovoltaics compared with manufacturing methods used today and open up possibilities for other optoelectronic applications as well. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Because of outstanding optical properties and non-vacuum solution processability of colloidal quantum dot (QD) semiconductors, many researchers have developed various light emitting diodes (LEDs) using QD materials. Until now, the Cd-based QD-LEDs have shown excellent properties, but the eco-friendly QD semiconductors have attracted many attentions due to the environmental regulation. And, since there are many issues about the reliability of conventional QD-LEDs with organic charge transport layers, a stable charge transport layer in various conditions must be developed for this reason. This study proposes the organic/inorganic hybrid QD-LEDs with Cd-free InP QDs as light emitting layer and inorganic ZrO2 nanoparticles as electron transport layer. The QD-LED with bottom emission structure shows the luminescence of 530 cd m−2 and the current efficiency of 1 cd/A. To realize the transparent QD-LED display, the two-step sputtering process of indium zinc oxide (IZO) top electrode is applied to the devices and this study could fabricate the transparent QD-LED device with the transmittance of more than 74% for whole device array. And when the IZO top electrode with high work-function is applied to top transparent anode, the device could maintain the current efficiency within the driving voltage range without well-known roll-off phenomenon in QD-LED devices. [ABSTRACT FROM AUTHOR]

The formation and reduction of pyramidal hillocks on InGaAs/InP(111)A grown by metal organic chemical vapor deposition were investigated. The triangular pyramidal hillocks were observed on the InGaAs surface on on-axis InP (111)A grown at 650 °C. The hillocks disappeared when the vicinal InP (111)A substrates with an off-axis angle >0.4° were applied. The step and terrace surface of InGaAs on 4.0°-off InP (111)A were obtained. InGaAs on on-axis InP (111)A exhibited a hole concentration, mobility of Hall effect measurement, and full width at half-maximum of X-ray diffraction as 1.0 × 1017 cm−3, 56 cm2/V s, and 140 arcsec, respectively. In contrast, InGaAs on 2.0°-off InP (111)A exhibited 2.3-1017 cm−3, 142 cm2/V s, and 63 arcsec, respectively. We suggest that off-axis substrates enable a reduction of stacking faults, which leads to considerable improvement of crystallinity. [ABSTRACT FROM AUTHOR]

A lattice-matched InGaAs and InAlAs superlattice (SL) was used to embed InAs quantum dots (QDs) on an InP(311)B substrate; this is called the digital embedding method (DEM). We controlled the emission wavelength of the InAs QDs by changing the period of the SL or the ratio of the thickness of InGaAs to that of InAlAs. In addition, we investigated the time-resolved photoluminescence (PL) of the InAs QDs using the DEM. The decay time of the PL from the QDs was estimated by fitting a single exponential curve and was 380 ps in the DEM sample and 700 ps in the reference sample with a conventional InGaAlAs barrier. The decay time was clearly altered by changing the embedding structure. Therefore, carrier dynamics could be controlled using the DEM. [ABSTRACT FROM AUTHOR]