Search

The industry is likely to witness more changes in the next decade than in the last 20 years, and the time to respond is now. The mix of markets driving the global automotive sales has changed yet again. Growth has shifted to markets such as the US, Western Europe and China, while the emerging markets have cooled off. And the pace of global vehicle sales growth is expected to slow over the next few years. Disruption has become the fundamental to the rapid evolution of the mobility ecosystem. Innovation is challenging established principles, from value proposition to cost drivers and product life cycles. Purchasing decisions made for each ride are influenced by factors including availability, comfort, ease of use, reliability ratings and pricing. Autonomous driving functions could not be realised without artificial intelligence. The computing power required for this is provided by chips that are specialised in parallel computing. Researchers are also working on new biologically inspired solutions and on quantum computers that promise even more computing power. [ABSTRACT FROM AUTHOR]

Single crystal InP was analyzed using high-resolution high-energy x-ray photoelectron spectroscopy (HAXPES). The HAXPES spectra of InP obtained using monochromatic Cr Kα radiation at 5414.8 eV include two survey scans (Al Kα and Cr Kα) and high-resolution spectra of In 2s, In 2p3/2, In 3s, In 3p, In 3d, In 4s, In 4d, P 1s, P 2s, and P 2p. [ABSTRACT FROM AUTHOR]

Positive aging has been reported to be effective for enhancing electroluminescence characteristics of quantum dot (QD) based optoelectrical devices. This study investigated the intricate mechanisms underlying the positive aging effect in quantum-dot light-emitting diodes (QLEDs) influenced by encapsulation with ultraviolet-curable resin. A 120-h analysis assessed the impact of the resin on the electron transport layer and emission layer, utilizing a strategically positioned perfluorinated ionomer (PFI) interlayer. The PFI layer effectively delayed the Al 2 O 3 formation at the zinc magnesium oxide (ZMO)/Al interface and further reduced the interactions within the QD/ZMO interface, thereby curtailing exciton quenching at the interfaces. The time-sequential effect of positive aging demonstrated that resin encapsulation effectively passivates the ZMO surfaces after 12 h. The positive aging facilitated the reaction between aluminum and oxygen from ZMO, contributing to Al 2 O 3 formation within 48 h of aging. Furthermore, positive aging passivated the defect states of the QD surface and the QD/ZMO interface, reducing exciton quenching at the QD or QD/ZMO interface. The enhanced electron injection and reduced exciton quenching resulted in aged InP QLEDs, exhibiting an external quantum efficiency of 12.04%. This is a significant increase from the 3.16% observed in the control device. Finally, a sequential mechanism of positive aging in InP QLEDs was devised, providing new insights into the time-related operation of aging agents. This study elucidates an advanced time-resolved mechanism of positive aging, thereby offering valuable insights into the intricate dynamics of excitons within the domain of QLED physics.

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Here, we report photocatalytic CO2 reduction with water to produce methanol using TiO2-passivated InP nanopillar photocathodes under 532 nm wavelength illumination. In addition to providing a stable photocatalytic surface, the TiO2-passivation layer provides substantial enhancement in the photoconversion efficiency through the introduction of O vacancies associated with the nonstoichiometric growth of TiO2 by atomic layer deposition. Plane wave-density functional theory (PW-DFT) calculations confirm the role of oxygen vacancies in the TiO2 surface, which serve as catalytically active sites in the CO2 reduction process. PW-DFT shows that CO2 binds stably to these oxygen vacancies and CO2 gains an electron (-0.897e) spontaneously from the TiO2 support. This calculation indicates that the O vacancies provide active sites for CO2 absorption, and no overpotential is required to form the CO2(-) intermediate. The TiO2 film increases the Faraday efficiency of methanol production by 5.7× to 4.79% under an applied potential of -0.6 V vs NHE, which is 1.3 V below the E(o)(CO2/CO2(-)) = -1.9 eV standard redox potential. Copper nanoparticles deposited on the TiO2 act as a cocatalyst and further improve the selectivity and yield of methanol production by up to 8-fold with a Faraday efficiency of 8.7%.

The surface transformation mechanisms upon annealing of epi-ready InP(001) substrates in the molecules arsenic flux were studied in situ by reflection high-speed electron diffraction (RHEED). The effect of the annealing temperature and arsenic flux rate on the removal of oxides from the InP surface as a result of thermal decomposition and chemical interaction of oxides with arsenic was studied. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Processes of diffusion of As and P atoms in InP and InAs, and atomic and energy structure of group-V vacancies and interstitial P and As atoms in InP and InAs have been investigated using density functional theory. Formation energies of group-V vacancies in InP and InAs and P and As interstitial atoms in InP and InAs have been calculated with hybrid functional. The main types of migration jumps have been determined, and the energy favorable migration paths and migration barriers of As and P atoms diffusion in InP and InAs via vacancies and interstitial atoms have been calculated using climbing image nudged elastic band method. In the case of diffusion of As and P atoms in InP and InAs via interstitial atoms the diffusion process occurs via indirect interstitial mechanism. The migration energy barriers for the vacancy diffusion mechanism are 1.5–2.0 eV, the migration energy barriers for the interstitialcy mechanism are 0.3–0.6 eV. The interstitial atoms have higher formation energies compared to the formation energies of the vacancies, and total activation energies of the diffusion are comparable for the vacancy and interstitialcy mechanisms. The obtained results will be useful for modeling of the diffusion processes in semiconductor structures based on InP and InAs. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract We report optical phonon vibration modes in ensembles of self-catalyzed InP/InAs/InP multi core-shell one-dimensional nanostructures (nanopillars and nanocones) grown on InP(111)B substrates using liquid indium droplets as a catalyst via metal-organic chemical vapor deposition. We characterized the Raman vibration modes of InAs E1(TO), InAs A1(TO), InAs E1(LO), InP E1(TO), InP A1(LO), and InP E1(LO) from the ensemble of as-grown nanostructures. We also identified second-order Raman vibration modes, associated with InP E1(2TO), E1(LO+TO), and E1(2LO), in the InP/InAs/InP core-shell nanopillars and nanocones. Raman spectra of InP/InAs/InP nanopillars showed redshift and broadening of LO modes at low-frequency branches of InAs and InP. Due to the polar nature in groups III–V nanowires, we observed strong frequency splitting between InAs E1(TO) and InAs A1(LO) in InP/InAs/InP nanocones. The Raman resonance intensities of InP and InAs LO modes are found to be changed linearly with an excitation power. By tilting the substrate relative to the incoming laser beam, we observed strong suppression of low-frequency branch of InP and InAs LO phonon vibrations from InP/InAs/InP nanocones. The integrated intensity ratio of InP E1(TO)/E1(LO) for both nanostructures is almost constant at 0-degree tilt, but the ratio of the nanocones is dramatically increased at 30-degree tilt. Our results suggest that Raman spectroscopy characterization with a simple substrate tilting method can provide new insights into non-destructive characterization of the shape, structure, and composition of the as-grown nanostructures for the wafer-scale growth and integration processing of groups III–V semiconducting hetero-nanostructures into nanoelectronics and photonics applications.

Nanostructures composed of dielectric, metallic or metalo-dielectric structures are receiving significant attention due to their unique capabilities to manipulate light for a wide range of functions such as spectral colors, anti-reflection and enhanced light-matter interaction. The optical properties of such nanostructures are determined not only by the shape and dimensions of the structures but also by their spatial arrangement. Here, we demonstrate the generation of vivid colors from nanostructures composed of spatially disordered metalo-dielectric (In/InP) nanopillar arrays. The nanopillars are formed by a single-step, ion-sputtering-assisted, self-assembly process that is inherently scalable and avoids complex patterning and deposition procedures. The In/InP nanopillar dimensions can be changed in a controlled manner by varying the sputter duration, resulting in reflective colors from pale blue to dark red. The fast Fourier transform (FFT) analysis of the distribution of the formed nanopillars shows that they are spatially disordered. The electromagnetic simulations combined with the optical measurements show that the reflectance spectra are strongly influenced by the pillar dimensions. While the specular and diffuse reflectance components are appreciable in all the nanopillar samples, the specular part dominates for the shorter nanopillars, thereby leading to a glossy effect. The simulation results show that the characteristic features in the observed specular and diffused reflectance spectra are determined by the modal and light-scattering properties of single pillars. While the work focuses on the In/InP system, the findings are relevant in a wider context of structural color generation from other types of metalo-dielectric nanopillar arrays.

Residual amplitude modulation of the phase modulator deployed in Pound-Drever-Hall frequency stabilization is an effect known to cause instabilities to the absolute wavelength of the stabilized laser. We present measurements and analysis of the residual amplitude modulation in an InP-based waveguide electro-optic phase modulator. The modulator is monolithically integrated in the output waveguide of a tuneable laser. The effects on the frequency stabilization of such a laser system to a reference etalon using a Pound-Drever-Hall frequency stabilization scheme are quantified. Frequency offset values in the stabilization point from the reference Fabry-Perot etalon resonance caused by the amplitude modulation are predicted and optimum operating points to minimize residual amplitude modulation are discussed. By operating an electro-refractive phase modulator at the proper bias point, we show that frequency offsets corresponding to less than 3 × 10-3 of the reference cavity full-width half-maximum can be achieved.

A high data rate RF-DAC and a power detector (PD) are designed and fabricated in a 250 nm indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. A communication link using the Tx-Rx over polymer microwave fiber (PMF) is measured. The link consists of a pulse amplitude modulation (PAM) modulator and a PD as a demodulator, as well as a one-meter-long dielectric waveguide. The working frequency range of the complete link is verified to be 110–150 GHz. The peak output power of the PAM modulator is 5 dBm, and it has a −3 dB bandwidth of 43 GHz. The PD consists of a parallel connected common emitter configured transistor and a common base configured transistor to suppress the odd-order harmonics at the PD’s output, as well as a stacked transistor to amplify the output signal. Tx and Rx chips, including pads, occupy a total area of only 0.83 mm2. The PMF link can support a PAM-4 signal with 22 Gbps data transmission, and a PAM-2 signal with 30 Gbps data transmission, with a bit error rate (BER) of

Flip-chip microbump (μ-bump) bonding technology between indium phosphide (InP) and silicon carbide (SiC) substrates for a millimeter-wave (mmW) wireless communication application is demonstrated. The proposed process of flip-chip μ-bump bonding to achieve high-yield performance utilizes a SiO2-based dielectric passivation process, a sputtering-based pad metallization process, an electroplating (EP) bump process enabling a flat-top μ-bump shape, a dicing process without the peeling of the dielectric layer, and a SnAg-to-Au solder bonding process. By using the bonding process, 10 mm long InP-to-SiC coplanar waveguide (CPW) lines with 10 daisy chains interconnected with a hundred μ-bumps are fabricated. All twelve InP-to-SiC CPW lines placed on two samples, one of which has an area of approximately 11 × 10 mm2, show uniform performance with insertion loss deviation within ±10% along with an average insertion loss of 0.25 dB/mm, while achieving return losses of more than 15 dB at a frequency of 30 GHz, which are comparable to insertion loss values of previously reported conventional CPW lines. In addition, an InP-to-SiC resonant tunneling diode device is fabricated for the first time and its DC and RF characteristics are investigated.

DC performances of depletion-mode 100 nm In0.53Ga0.47As/InP high electron mobility transistor (HEMT) heterogeneously integrated to silicon substrate by SiO2–SiO2 bonding were investigated by using numerical simulation. Effects of fixed charges at the InP/SiO2 interface, the SiO2/SiO2 bonding interface, and the SiO2/Si interface on HEMT are compared. Among these charges, dc characteristics of HEMT are most sensitive to fixed charges at the InP/SiO2 interface. With the density of negative fixed charges at the InP/SiO2 interface increasing from − 5 × 1010 to − 1 × 1012 cm−2, the energy band exhibits an upward bending and leads to a decrease of electron concentration in the channel. The threshold voltage shifts from −1.03 to −0.85 V and the output current exhibits a decrease of 96 mA/mm under the gate bias of 0 V; meanwhile, the breakdown voltage increases from 4.4 to 6.5 V under the gate bias of −1.6 V. A shift of C−V curves in pace with transfer characteristic curves further confirms that the two-dimensional electron gas (2DEG) channel of HEMT is indeed influenced by fixed charges at the InP/SiO2 interface. As a comparison, the other two charges exhibit a relatively weak influence, where the increase of charges at the SiO2/SiO2 bonding interface results in a 36 mV shift of threshold voltage and 20 mA/mm decrease of output current, and the charges at the SiO2/Si interface only cause 6 mV shift of threshold that can almost be ignored. We proposed an appropriate increase of InP layer thickness to mitigate the impact of fixed charges on the transfer and output characteristic of HEMTs. [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]

Copyright of Technisches Messen is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report uniform Type-II GaInAsSb/InP UTC-PDs, and compare their performance to devices fabricated with GaAsSb uniform and graded (composition and doping) absorbers of the same thickness. The quaternary UTC-PDs show a transit limited bandwidth of 274 GHz in contrast to 107 and 185 GHz for uniform and graded GaAsSb absorber UTC-PDs. Because the uniform quaternary and ternary UTC-PDs only differ in their absorber material, the findings conclusively demonstrate enhanced transport in GaInAsSb. Performance comparison to GaInAs-based devices from the literature suggest that GaInAsSb is a superior absorber material for λ = 1.55 μm high-speed photodetectors. Additionally, the external responsivity of the GaInAsSb UTC-PDs (0.094 A/W) is ∼34% higher than the GaAsSb PDs (0.070 A/W). This is the first demonstration of a quaternary GaInAsSb absorber in UTC-PDs. [ABSTRACT FROM AUTHOR]

A self-powered ITO/ZnO/InP heterojunction photodetector has been demonstrated with a 10-nm ZnO interfacial layer deposited by atomic layer deposition as a hole-blocking layer. The presence of a valence band offset between InP and ZnO enhances the photocurrent. The valence band offset between InP and ZnO creates a sufficient barrier for hole movement. Low surface recombination under 520-nm laser irradiation produced maximum photoresponsivity of 44.2 mAW−1 with an illumination power of 1 µW at zero bias. The ZnO-passivated self-powered photodetector shows fast response and improved photo-detecting properties. Furthermore, the highly sensitive photodetectors are demonstrated to record the heart pulse wave by measuring relative changes in blood volume of the finger vessels. [ABSTRACT FROM AUTHOR]

Light-emitting diodes based on colloidal quantum dots (QLEDs) show a good prospect in commercial application due to their narrow spectral linewidths, wide color range, excellent luminance efficiency, and long operating lifetime. However, the toxicity of heavy-metal elements, such as Cd-based QLEDs or Pb-based perovskite QLEDs, with excellent performance, will inevitably pose a serious threat to people’s health and the environment. Among heavy-metal-free materials, InP quantum dots (QDs) have been paid special attention, because of their wide emission, which can, in principle, be tuned throughout the whole visible and near-infrared range by changing their size, and InP QDs are generally regarded as one of the most promising materials for heavy-metal-free QLEDs for the next generation displays and solid-state lighting. In this review, the great progress of QLEDs, based on the fundamental structure and photophysical properties of InP QDs, is illustrated systematically. In addition, the remarkable achievements of QLEDs, based on their modification of materials, such as ligands exchange of InP QDs, and the optimization of the charge transport layer, are summarized. Finally, an outlook is shown about the challenge faced by QLED, as well as possible pathway to enhancing the device performance. This review provides an overview of the recent developments of InP QLED applications and outlines the challenges for achieving the high-performance devices.

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]

Growth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth. [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]

半导体纳米晶具有量子尺寸效应和独特的光学性质,可广泛地应用在光电器件、生物标记、太阳能电 池、光催化等方面,因此半导体纳米晶成为越来越多研究者研究的热点。但在诸多的应用限制因素中,高性能的 QDs材料(II-VI或IV-VI)通常含有镉或铅等剧毒的元素,批量生产和使用这类材料不仅对人体有着极大的 伤害,还会引起环境和生态问题。因此低毒性能的QDs材料的设计和研发是目前研究的前沿之一。研究人员通 过控制反应条件、表面包裹以及掺杂等对磷化铟(InP)材料的性能进行调控,使之能够更好地应用于各个领域之 中. [ABSTRACT FROM AUTHOR]

We demonstrated the feasibility of using InP (100) substrates, a different indium source, for the synthesis of In2O3 nanowires by the vapor–liquid–solid (VLS) method using a 20-nm-thick Au layer as a catalyst. By varying the thickness of the Au layer and the growth temperature (T), the nanowires showed different morphologies. The nanowires grew along the (100) direction and had perfect crystallinity and lengths up to several hundreds of micrometers. The configured field-effect transistor revealed an n-type behavior with 115 μA of the drain-source current, IDS, under 1.0 V of gate voltage, VDS, at 1.33 × 10−4 kPa of pressure and temperature of 20°C. This result indicates that it is feasible to use different In sources to synthesize In2O3 nanowires by the VLS method for electronic devices. [ABSTRACT FROM AUTHOR]

The utilization of InP-based quantum dots (QDs) as alternative luminescent nanoparticles to cadmium-based QDs is actively pursued. However, leveraging their luminescence for solid-state applications presents challenges due to the sensitivity of InP QDs to oxidation and aggregation-caused quenching. Hence, an appealing strategy is to protect and disperse InP QDs within hybrid materials. Metal-organic frameworks (MOFs) offer a promising solution as readily available crystalline porous materials. Among these, MOF-5 (composed of {Zn 4 O} 6+ nodes and terephthalate struts) can be synthesized under mild conditions (at room temperature and basic pH), making it compatible with InP QDs. In the present work, luminescent InP/ZnS QDs are successfully incorporated within MOF-5 by two distinct methods. In the bottle around the ship (BAS) approach, the MOF was synthesized around the QDs. Alternatively, in the ship in the bottle (SIB) strategy, the QDs were embedded via capillarity into a specially engineered, more porous variant of MOF-5. Comparative analysis of the BAS and SIB approaches, evaluating factors such as operational simplicity, photoluminescence properties, and the resistance of the final materials to leaching were carried out. This comparative study provides insights into the efficacy of these strategies for the integration of InP/ZnS QDs within MOF-5 for potential solid-state applications in materials chemistry., Competing Interests: The authors declare no conflict of interest.

Crystal phase transitions can form a new type of heterojunction with different atomic arrangements in the same material: crystal phase heterojunction (CPHJ). The CPHJ has an inherently strong impact on band engineering without concerns over critical thicknesses with misfit dislocations and a semiconductor-metal transition. In-plane CPHJ was recently demonstrated in two-dimensional (2D) transition-metal dichalcogenide (TMD) materials and utilized for conventional planar field-effect transistor applications. However, scalability such as gate electrostatic control, miniaturization, and multigate structure have been limited because of the geometrical issue. Here, we demonstrated a transistor using the CPHJ with a vertical gate-all-around structure by forming a CPHJ in conventional III-V semiconductors. The CPHJ, composed of wurtzite InP nanowires with zincblende InP substrates, showed an atomically flat heterojunction without dislocations and indicated a Type-II band discontinuity across the junction. The CPHJ transistor had moderate to good gate electrostatic controllability with high on-state currents and transconductance. The CPHJ offer will provide a new switching mechanism and add a new junction and device design choice to the long history of transistors.

Indium phosphide (InP) quantum dots (QDs) are considered the most promising alternative for Cd and Pb-based QDs for lighting and display applications. However, while core-only QDs of CdSe and CdTe have been prepared with near-unity photoluminescence quantum yield (PLQY), this is not yet achieved for InP QDs. Treatments with HF have been used to boost the PLQY of InP core-only QDs up to 85%. However, HF etches the QDs, causing loss of material and broadening of the optical features. Here, we present a simple postsynthesis HF-free treatment that is based on passivating the surface of the InP QDs with InF 3. For optimized conditions, this results in a PLQY as high as 93% and nearly monoexponential photoluminescence decay. Etching of the particle surface is entirely avoided if the treatment is performed under stringent acid-free conditions. We show that this treatment is applicable to InP QDs with various sizes and InP QDs obtained via different synthesis routes. The optical properties of the resulting core-only InP QDs are on par with InP/ZnSe/ZnS core-shell QDs, with significantly higher absorption coefficients in the blue, and with potential for faster charge transport. These are important advantages when considering InP QDs for use in micro-LEDs or photodetectors.

InP-based colloidal nanocrystals are being developed as an alternative to cadmium-based materials. However, their optical properties have not been widely studied. In this paper, the fundamental magneto-optical properties of InP/ZnSe/ZnS nanocrystals are investigated at cryogenic temperatures. Ensemble measurements using two-photon excitation spectroscopy revealed the band-edge hole state to have 1 S h symmetry, resolving some controversy on this issue. Single nanocrystal microphotoluminescence measurements provided increased spectral resolution that facilitated direct detection of the lowest energy confined acoustic phonon mode at 0.9 meV, which is several times smaller than the previously reported values for similar nanocrystals. Zeeman splitting of narrow spectral lines in a magnetic field indicated a bright trion emission. A simple trion model was used to identify a positive trion charge. Furthermore, the Zeeman split spectra allowed the direct measurement of both the electron and hole g -factors, which match existing theoretical predictions.

In this paper, the microwave characteristic of photosensitive material InP irradiated by different optical signals is studied based on the coaxial resonant cavity. The coaxial resonant cavity sensor has an operating frequency range from 1 to 4 GHz, an operating mode of TEMn/4, and a quality factor of 8000 or more. According to the theory of semiconductor and electromagnetic field, the equation describing the relationship between the irradiation power and the quality factor of the coaxial resonator is derived. Additionally, in the short-time irradiation experiment, the variation of microwave characteristics of InP with irradiation power of 10mW, 50mW, 100mW, and 250mW is studied by frequency-domain and time-domain scanning methods, respectively. The measurement results indicate that the microwave characteristic variation of the InP under short-time weak power irradiation is mainly caused by the non-thermal effect, while the thermal effect is not obvious. In order to investigate the influence of thermal effect on the microwave characteristic of InP under continuous illumination, taking the irradiation power of 100mW as an example, the irradiation experiment with a duration of 1 min is performed on the InP. The thermal and non-thermal effects at the moment of opening and closing of the monochrome light source and during irradiation are analyzed. Furthermore, the stability and response speed of the system are analyzed and tested, and the measurement results are in good agreement with the theoretical analysis.

The photovoltaic (PV) market today is dominated by silicon (Si)-based solar cells, which, however, can be improved in performance and cost by developing technologies that use less material. We propose an indium phosphide (InP) nanoresonator array on silicon ultra-thin film with a combined thickness of 0.5 μm to 2 μm as a solution to minimize cost and maximize power efficiency. This paper focuses on simultaneously achieving broadband antireflection and enhanced absorption in thin-film Si with integrated InP nanodisk arrays. Electromagnetic simulations are used to design and optimize the reflectance and absorption of the proposed design. By varying the height and radius of the InP nanodisks on the Si substrate, together with the array pitch, a weighted reflectance minimum, with respect to the AM1.5 solar spectrum, of 2.9% is obtained in the wavelength range of 400 nm to 1100 nm. The antireflective properties are found to be a combination of a Mie-resonance-induced strong forward-scattering into the structure and an effective index-matching to the Si substrate. In terms of absorption, even up to 2 μm from the Si surface the InP nanodisk/Si structure consistently shows superior performance compared to plain Si as well as a Si nanodisk/Si structure. At a depth of 500 nm from the surface of the substrate, the absorption values were found to be 47.5% for the InP nanodisk/Si structure compared to only 18.2% for a plain Si substrate. This shows that direct bandgap InP nanoresonator arrays on thin-film Si solar cells can be a novel design to enhance the absorption efficiency of the cell.

Through the synthetic development of sophisticated core/shell heterostructures, the fluorescent properties of quantum dots (QDs) have been steadily improved to a level that can ultimately meet the industrial demands, but their reliability is still insufficient, particularly showing low fluorescence stability against degradable conditions. As one solution to this issue, an additional physical barrier typically with an oxide phase has been introduced to protect the QD surface from the environment. In this work, a strategy for improving the stability of QDs involving the passivation of their surfaces with zirconium propoxide (Zr(PrO)4) is suggested. Multi-shelled green QDs of InP/ZnSeS/ZnS were first synthesized, and then their surfaces were in-situ-treated with Zr(PrO)4. To confirm the presence of Zr(PrO)4-derived species on the QD surfaces, chemical analyses of the Zr(PrO)4-treated QDs were performed through Fourier transform infrared, X-ray photoelectron, and inductively coupled plasma optical emission spectroscopic measurements. A photostability test of two comparative InP/ZnSeS/ZnS QDs – one treated without and one with Zr(PrO)4 – was performed by exposing their dispersions to ultraviolet (UV) irradiation for prolonged periods of time, up to 120 h. It was revealed that Zr(PrO)4 treatment is highly effective in improving fluorescence retention and colloidal stability.

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]

A high-responsivity 3D graphene/InGaAs/InAs/InAlAs/Insb/InP HEMT two-dimensional electron gas (2DEG) photodetector is investigated and simulated using DevEdit and ATLAS 3D under SILVACO Tools. The InAs donor layer above the 2DEG contributes to the photocurrent using the InSb channel layer and graphene in the gate for light absorption. An illumination drain current equal to 57.5 mA was obtained with a rejection ratio (illumination current/dark current) equal to 1.02 A/W and 0.5 × 10−6 A/W available photocurrent, with high responsivity equal to 15.3 × 103 A/W at 100 nm wavelength and 100 GHz bandwidth. This property makes the device a suitable candidate for detection in the UV region of the spectrum. It can also be used in a number of medical, military and space applications. [ABSTRACT FROM AUTHOR]

Featured Application: On-chip optical reading of magnetic memory processed as ultrathin magnetic claddings on photonic waveguides. Design and simulations of an integrated photonic device that can optically detect the magnetization direction of its ultra-thin (∼12 nm) metal cladding, thus 'reading' the stored magnetic memory, are presented. The device is an unbalanced Mach Zehnder Interferometer (MZI) based on InP Membrane on Silicon (IMOS) platform. The MZI consists of a ferromagnetic thin-film cladding and a delay line in one branch, and a polarization converter in the other. It quantitatively measures the non-reciprocal phase shift caused by the Magneto-Optic Kerr Effect in the guided mode which depends on the memory bit's magnetization direction. The current design is an analytical tool for research exploration of all-optical magnetic memory reading. It has been shown that the device is able to read a nanoscale memory bit (400 × 50 × 12 nm) by using a Kerr rotation as small as 0.2 ∘ , in the presence of a noise ∼10 dB in terms of signal-to-noise ratio. The device is shown to tolerate performance reductions that can arise during the fabrication. [ABSTRACT FROM AUTHOR]

Graphene and P-type indium phosphide (P-InP) could be combined by van der Waals forces to form a Schottky junction, which can be applied in photodetection. This study reported a graphene/P-InP Schottky junction near-infrared photodetector with a 3-nm-thick Al 2 O 3 passivation layer and investigated the photoelectric characteristics of such device. As a result, the near-infrared photodetector had a Schottky barrier of 0.89 eV. Besides, this device had a significant response to the wavelength of 808 nm near-infrared light with responsivity and detectivity up to 5.2 mA/W and 1.3 × 10 10 cm Hz 1 / 2 W - 1 , respectively, under a reverse bias voltage of 0.4 V. It is expected that the Graphene/P-InP Schottky junction near-infrared photodetector with an Al 2 O 3 passivation layer may play a vital role in the field of optoelectronic devices in future. [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]

This article describes the design and performance of a 140-GHz SiGe and a 100-GHz InP triple-stacked HBT distributed amplifier with active bias terminations. The active bias network is configured to extend the practical low-frequency operation while maintaining gain flatness and linearity. Triple-stacked HBTs are used to increase the gain–bandwidth and linear output capability. The SiGe design is based on HBTs with a peak ƒT/ƒmax of 300/350 GHz and achieves 11.7 dB of gain and a bandwidth from baseband to 140 GHz. The InP HBT design is based on DHBTs with a peak ƒT/ƒmax of 250/250 GHz and obtains a gain of 10.8 dB and a bandwidth of 100 GHz. Although the SiGe design achieves 1.5 times higher gain–bandwidth, the InP DHBT design achieves ~3–4.5 dB greater IP3, P1~dB, and P3 ~dB while consuming only ~23% higher dc power. These results represent the first broadband performance comparison of near-identical (apples–apples) DA designs implemented in SiGe and InP HBT device technologies. Although there are previous reports of larger bandwidth distributed amplifiers in both InP and SiGe technologies demonstrated up through 200 GHz, the InP and SiGe monolithic microwave integrated circuits (MMICs) described in this article are believed to represent the highest bandwidths reported for HBT DAs using practical on-chip active bias terminations. [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]

Highly efficient and fabrication-error-resistant InP/ InGaAsP polarization rotator based on the half-ridge waveguide is experimentally demonstrated. A thin InAlAs layer is embedded inside the InGaAsP core layer to provide 20-fold etching selectivity with respect to InGaAsP, enabling precise control of the dry-etched core layer thickness. The designed device is fabricated to show a high polarization conversion efficiency of more than 95% with a large etching time tolerance of ±16%. Demonstrated scheme offers a practical path towards realizing compact and low-cost InP-based monolithic dual-polarization transceivers with on-chip polarization (de)multiplexers. [ABSTRACT FROM AUTHOR]

Indium phosphide quantum dots (QDs) have drawn attention as alternatives to cadmium- and lead-based QDs that are currently used as phosphors in lamps and displays. The main drawbacks of InP QDs are, in general, a lower photoluminescence quantum yield (PLQY), a decreased color purity, and poor chemical stability. In this research, we attempted to increase the PLQY and stability of indium phosphide QDs by developing lattice matched InP/MgSe core–shell nanoheterostructures. The choice of MgSe comes from the fact that, in theory, it has a near-perfect lattice match with InP, provided MgSe is grown in the zinc blende crystal structure, which can be achieved by alloying with zinc. To retain lattice matching, we used Zn in both the core and shell and we fabricated InZnP/ZnxMg1–xSe core/shell QDs. To identify the most suitable conditions for the shell growth, we first developed a synthesis route to ZnxMg1–xSe nanocrystals (NCs) wherein Mg is effectively incorporated. Our optimized procedure was employed for the successful growth of ZnxMg1–xSe shells around In-(Zn)P QDs. The corresponding core/shell systems exhibit PLQYs higher than those of the starting In-(Zn)P QDs and, more importantly, a higher color purity upon increasing the Mg content. The results are discussed in the context of a reduced density of interface states upon using better lattice matched ZnxMg1–xSe shells. [ABSTRACT FROM AUTHOR]

In this paper, the microwave characteristics of typical photosensitive material InP under different light irradiation are studied. The measurement sensor is a reflection-type hemispherical quasi-optical resonator with an operating frequency range from 20 to 40 GHz, an operating mode of TEM00q, and a quality factor of 18,000 or more. For the short-time irradiation experiment, the variation of InP microwave characteristics with the irradiation power of 20 mW, 60 mW, 100 mW, and 200 mW, is studied by frequency-domain and time-domain scanning methods, respectively. The measurement results indicate that the microwave characteristics of InP change significantly even under weak light irradiation. Taking 100 mW and 200 mW irradiation power as examples, the long-time irradiation experiment performed on InP lasting 1.5 min is carried out. The measurement result curves clearly show the influence of the thermal and non-thermal effects on the InP microwave characteristics at the instant of the monochrome light source opening and closing and during irradiation. Furthermore, the temperature distribution of InP during 200 mW irradiation is real-time imaged by a thermal infrared imager to verify the existence of thermal effect during irradiation. The measurement results are in good agreement with the theoretical analysis. The microwave properties of InP under short-time and long-time irradiation are analyzed by frequency-domain and time-domain scanning methods, especially the effects of thermal and non-thermal on microwave properties during long-term irradiation. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the design features of avalanche photodiode architectures with separated absorption (InGaAs) and multiplication (InAlAs) regions. Two architectures are considered: p+–M–с–i–n+- and p+–i–с–M–n+-types implemented in InGaAs/InAlAs/InP heteroepitaxial structures (HES). Three main layers, absorbing (i), charge (c), and multiplying (M), were mandatory for each architecture. Matrices of photosensitive elements were formed using data from InGaAs/InAlAs/InP HES grown via MOS hydride epitaxy (MOSHE) method. Photocurrent multiplication factors, which varied from 1 to 18–25 in the range of reverse bias voltages of U = 8–14 V, were calculated based on the studied current–voltage characteristics of avalanche elements in the matrices. [ABSTRACT FROM AUTHOR]