Phosphide Layers Research Articles

Construction of iron-doped nickel cobalt phosphide nanoparticles via solvothermal phosphidization and their application in alkaline oxygen evolution

Multi-metallic phosphides offer the possibility to combine the strategies of surface reconstruction, electronic interaction and mechanistic pathway tuning to achieve high electrocatalytic oxygen evolution activity. Here, iron-doped nickel cobalt phosphide nanoparticles (FexCoyNi2-x-yP) with the crystalline NiCoP phase are for the first time synthesized by the solvothermal phosphidization method via the reaction between metal–organic frameworks and white phosphorus. When used to electrochemically catalyze oxygen evolution reaction (OER), the Fe0.4Co0.8Ni0.8P supported by nickel foam requires only 248 mV overpotential to achieve 10 mA cm−2 current densities, and is robust towards the long-term OER in 1 M KOH. The higher number of electrochemically active sites can account for the good OER activity, along with the improved intrinsic activity which is caused by the electron interaction that optimizes the adsorption energy of hydroxyl intermediates, and that increases the acidity of high-valent metal centers. The OER mechanistic pathway involves both adsorbate and lattice oxygen. Surface conversion is observed after OER in alkaline solution, and metal phosphide layer transforms to metal oxides and (oxy)hydroxides.

CoMoP hole transfer layer functionally enhances efficiency and stability of BiVO4 based photoanode for solar water splitting

Engineering the hole transfer layer is a promising approach to suppress the bulk charge recombination of photoanodes for enhancing solar water splitting performance. Herein, functional cobalt-molybdenum bimetallic phosphide (CoMoP) layer are inserted between bismuth vanadate (BiVO4) and NiFeOx oxygen evolution cocatalyst (OEC) as hole transfer layer to construct an integrated photoanode (NiFeOx/CoMoP/BiVO4). This state-of-the-art NiFeOx/CoMoP/BiVO4 photoanode not only achieves a superior photocurrent density of 5.82 mA/cm2 at 1.23 V vs a reversible hydrogen electrode (vs RHE), but also an outstanding 60 h long-term photostability (100 mW/cm2). Such excellent PEC performance can be attributed to the engineering CoMoP hole layer in NiFeOx/BiVO4, promoting hole transfer, retarding bulk charge recombination and accelerating the surface water oxidation kinetics. This study contributes to the role of the hole transfer layer and sheds light on the development of effective and stable photoanodes for PEC water splitting.

Conformal growth of GaP on high aspect ratio Si structured surface via plasma-enhanced atomic layer deposition

This article is concerned with the study of conformal growth of thin gallium phosphide (GaP) layers by plasma-enhanced atomic layer deposition (PE-ALD) on a Si structured surface. GaP layers were deposited on (100) silicon wafers with a structured surface in the form of silicon microcolumns and black silicon. Deposition process were carried out at temperature of 380 °C using trimethylgallium and phosphine precursors. According to transmission electron microscopy (TEM), GaP layers deposited by this method conformally grown on the high aspect ratio structured silicon surface. The energy-dispersive X-ray spectroscopy (EDX) study show that the distribution of the main components of the GaP layer is uniform alongside surface of the silicon microcolumns and wires. High resolution TEM study confirms that GaP layers on the surface of silicon microcolumns and wires are epitaxial with the inclusion of twin lattice defects. Therefore, this deposition method can be used for the conformal deposition of thin crystalline layers of GaP on structured silicon surfaces with a high aspect ratio.

Phase‐Bridged Hierarchical Catalysts for Efficient and Stable Water Electrolysis

AbstractThe design and synthesis of low‐cost electrocatalysts with high catalytic activity and long‐term stability is a challenging task. This study utilizes a combination of electronic tuning and surface reconstruction to synthesize a ternary layered double hydroxide (LDH)/phosphide (P−NiCuFe−LDH) hierarchical‐structure catalyst that improves the kinetics of the hydrogen/oxygen evolution reactions in water electrolysis by facilitating the thermodynamically limited reaction pathways. Spectroscopic analyses indicate synergistic electronic interactions among the metal atoms in the LDH and phosphide layers via the P‐bridge effect. This cross‐layer interaction optimizes the electron transport pathways and reaction kinetics, enabling the proposed hierarchical electrocatalyst to exhibit high intrinsic activity. Theoretical calculations confirm the configuration of the cross‐phase bridges and elucidate the origin of the enhanced electrocatalytic effect of P−NiCuFe−LDH. For overall water splitting, the P−NiCuFe0.06−LDH || P−NiCuFe0.06−LDH system requires only 1.517 V to attain a current density of 10 mA cm−2. The P−O‐containing surface (generated in situ during water electrolysis) prevents metal‐ion leaching and endows P−NiCuFe−LDH with excellent operational stability; as demonstrated by the continuous long‐term stability test over 1000 h with negligible performance degradation. This study provides important insights into the design of rational hierarchical structures for a wide range of applications beyond water splitting.

Ni-based heterostructure with protective phosphide layer to enhance the oxygen evolution reaction for the seawater electrolysis

The seawater electrolysis to generate hydrogen is a promising method to supply clean energy because the hydrogen has a high energy density and near zero carbon emissions. However, the competitive chlorine evolution reaction (ClER) and chloride-induced corrosion have a significant negative effect for the oxygen evolution reaction (OER), which leads to low current density and poor catalytic stability of the seawater electrolysis. Here, a heterostructure of NiO/Ni3S2 coated by protective Ni5P4 layer is designed as an OER electrocatalyst (NiO/Ni3S2@Ni5P4) for seawater electrolysis. Because of the enhanced capacity of electron transfer, accelerated reaction kinetics, and increased exposed active sites, the resulting electrocatalyst achieves the OER overpotential of 280 and 310 mV at 10 mA cm−2 for the freshwater and seawater electrolysis, respectively. More importantly, the electrocatalyst presents excellent catalytic stability of OER over 100 h at 100 mA cm−2 with negligible decay due to its good corrosion resistance. This work offers new inspiration for the design of effective electrocatalysts for the seawater electrolysis.

Plasma enhanced atomic layer deposition of crystallized gallium phosphide on Si with tri-Ethylgallium and tri-tert-Butylphosphine

25 ∼ 30 nm thick polycrystalline gallium phosphide (GaP) films with high P / Ga atomic ratios were deposited on Si (100) using a plasma enhanced atomic layer deposition (PE-ALD) process with triethyl gallium (TEG), tri-tertiary butyl phosphide (tri-TBP), and atomic hydrogen. The key is chemical functionalization of the Si (100) surface since the wet-cleaned Si surface is nearly inert to TEG and tri-TBP. In-situ Auger spectroscopy was employed to identify the most successful functionalization which employed a gas phase mixture of atomic hydrogen and tri-TBP consistent with formation of a surface phosphide layer on Si(100); this layer efficiently nucleated the PE-ALD of GaP. The crystallinity and surface roughness of GaP films were tuned by controlling the pulse length of atomic H plasma, showing the self-limiting ALD film growth with 2.7 Å/cycle. The optimal crystallized GaP thin film on 6°-miscut Si showed local epitaxy growth of homogeneous GaP epi-layers in transmission electron microscopy (TEM).

Facile layer-by-layer fabrication of semiconductor microdisk laser particles.

Semiconductor-based laser particles (LPs) with exceptionally narrowband spectral emission have been used in biological systems for cell tagging purposes. Fabrication of these LPs typically requires highly specialized lithography and etching equipment, and is typically done in a cleanroom environment, hindering the broad adoption of this exciting new technology. Here, using only easily accessible laboratory equipment, we demonstrate a simple layer-by-layer fabrication strategy that overcomes this obstacle. We start from an indium phosphide (InP) substrate with multiple epitaxial indium gallium arsenide phosphide (InGaAsP) layers which are sequentially processed to yield LPs of various compositions and spectral properties. The LPs isolated from each layer are characterized, exhibiting excellent optical properties with lasing emission full width at half maximum as narrow as < 0.3 nm and typical thresholds of approximately 6 pJ upon excitation using a 3 ns pulse duration 1064 nm pump laser. The high quality of these particles renders them suitable for large-scale biological experiments including those requiring spectral multiplexing.

Iron and Oxygen Codoped Cobalt Phosphide Solvothermally Prepared from a Metal–Organic Framework for Oxygen Evolution

The preparation of highly active and low-cost electrocatalysts is a major challenge for water electrolysis. Here, iron and oxygen codoped cobalt phosphide nanoparticles (O–Co1–xFexPy, x = 0–0.42) are prepared by reacting metal–organic framework with phosphorus under solvothermal conditions. When electrochemically catalyzing the oxygen evolution reaction (OER) in 1 M KOH, O–Co0.58Fe0.42Py supported on the nickel foam exhibits the best activity, with only 232 mV overpotential to reach 10 mA cm–2 OER current densities. O–Co0.58Fe0.42Py is robust toward the long-term OER, and surface phosphide layers transform to (oxy)hydroxides during the OER. O–Co1–xFexPy also shows better OER activity than Co3O4 nanoparticles and commercial IrO2. The abundant electrochemically active sites exposed by the highly porous morphology and the electron interactions between Co and Fe that accelerate the OER intermediate adsorption process could account for the observed high OER activity.

Gallium phosphide-on-insulator integrated photonic structures fabricated using micro-transfer printing

Gallium phosphide-on-insulator emerged recently as a promising platform for integrated nonlinear photonics due to its intrinsic material properties. However, current integration solutions, using direct die-to-wafer bonding, do not support spatially localized integration with CMOS circuits which induce a large and expensive footprint material need. Here we demonstrate the transfer of gallium phosphide layers to an oxidized silicon wafer using micro-transfer printing as a new approach for versatile future (hybrid) integration. Using this novel approach, we demonstrate as a proof of concept the fabrication of gallium phosphide-on-insulator ring resonators with Q-factors as high as 35,000.

Heterostructure engineering of the Fe-doped Ni phosphides/Ni sulfide p-p junction for high-efficiency oxygen evolution

Regulating charge distribution through heterostructure engineering is an encouraging approach to achieving efficient alkaline water electrolysis. Here, a Fe-doped Ni phosphides/Ni sulfide p-p heterojunction (NiFe-PS) for oxygen evolution reaction (OER) is constructed on nickel foam. It is shown that the built-in electric field at the interface of Fe-doped Ni phosphides/Ni sulfide facilitates the charge transfer and modifies the electronic properties of the catalyst, thereby enhancing its conductivity and catalytic activity. Profiting from the rational electronic structure modulation, the designed NiFe-PS electrode possesses excellent OER performance among phosphides with low overpotentials of 204 and 256 mV at current densities of 10 and 100 mA cm-2, respectively. Meanwhile, the prepared catalyst displays high stability in the long-term chronopotentiometric test (125 h @ 100 mA cm-2). Structural characterizations confirm that the outer phosphide layer can withstand long-term surface oxidation and operate as a robust shield to prevent oxidation of the inner sulfide, ensuring rapid electron transport within the catalyst throughout the OER process.

Electrocatalytic layers for hydrogen evolution reaction based on nickel phosphides: cost-effective fabrication and XPS characterization

The development of efficient electrocatalysts based on Pt-free materials is a crucial step for the maturation of competitive water splitting technologies able to sustain the upcoming hydrogen-based economy. In this context, the present work optimizes a codeposition/annealing methodology to produce electrocatalytic layers for the hydrogen evolution reaction (HER) based on one of the most promising alternatives to Pt-based catalysts: nickel phosphides. A nickel–phosphorus solid solution is codeposited with red phosphorus microparticles and the obtained composites are annealed to promote interdiffusion and reaction between nickel and phosphorus. The experimentation carried out demonstrates that the properties of the final phosphide layers depend on the conditions employed in both the codeposition step and the annealing step. It is fundamental to evaluate and optimize the NiP/P codeposition process, and it is also important to understand the influence of annealing time and temperature on the microstructure and HER performance of the layers obtained. X-ray photoelectron spectroscopy (XPS) is employed to evaluate the phase composition at the surface, highlighting the presence of a top layer characterized by a Ni2P/Ni12P5 ratio significantly lower than the value found in the bulk of the coating. Annealed NiP/P layers are tested for HER in 0.5 M sulphuric acid solution. The tests demonstrate a clear correlation between the Ni2P/Ni12P5 ratio on the surface and the overpotential for HER. Coherently, when the outer Ni12P5-rich layer is mechanically removed, lower overpotentials are observed (169.5 mV vs. RHE for 10 mA cm−2).

Indium phosphide and black phosphorus employed surface plasmon resonance sensor for formalin detection: numerical analysis

A hybrid Kretschmann configuration-based surface plasmon resonance biosensor is investigated to detect formalin in water was proposed. The modification is done in the conventional sensor by adding the indium phosphide (InP) and black phosphorus (BP) material layer. The silver (Ag) metal thickness is 45 nm, the optimized thickness of the metal for the proposed design. The thickness of the InP and BP materials 2 and 0.34 nm are considered. For three InP layers and one BP layer, the maximum sensitivity of 250.2 deg / RIU is achieved. The BP layer is used to improve the biorecognition ability of the sensor. The performance of the sensor is analyzed using the angular interrogation method. The proposed sensor is investigated for the aqueous sensing medium. The InP is an air-stable semiconductor material and has applications in chemical, medical, and biological fields.

Investigation of the zinc diffusion process into epitaxial layers of indium phosphide and indium-gallium arsenide grown by molecular beam epitaxy

The results of an investigation of the peculiarities of the zinc diffusion process into epitaxial layers of indium phosphide and indium-gallium arsenide aimed at the fabrication of an avalanche photodiode for a single-photon detector are presented. The diffusion of zinc into indium phosphide through an intermediate layer of indium-gallium arsenide ensures better surface quality compared with the direct diffusion of zinc into the indium phosphide layer. We discovered that systems such as a quartz reactor with resistive heating with an internal solid-state source of zinc vapor and the reactor of a metal-organic chemical vapor deposition setup with hydrogen as a carrier gas make it possible to achieve similar concentrations of doping p-type impurity, which exceed 2×1018cm−3. The depth of zinc diffusion in the indium phosphide layer ranged from 2 to 3.5 µm, depending on the temperature and duration of the diffusion process. Such depths are required for fabrication of effective avalanche photodiodes.

Dual gate material (Au and Pt) based double-gate MOSFET for high-speed devices

Aluminium Gallium Arsenide (AlGaAs) is a semiconductor material used in the latest design of double heterostructure laser diodes. This semiconductor is mostly available in the arbitrary alloy form between Gallium Arsenide and Aluminium Arsenide. It is derived from the Tri-MethylGallium (TMG/TMGa), and Arsine (AsH3), both the chemicals are pyrophoric and toxic. The resistance is less between source and drain contacts in the case of AlGaAs so that it has been proposed as a material to grow contacts on Indium Phosphide (InP) layer. The AlGaAs uses an ion implantation model for a design purpose which lowers the thermal power while the operation of the device. The parasitic capacitance has to be taken care of while designing a device using this material since the capacitance affects much in the AlGaAs based devices. The average velocity of the electrons has been observed to be increased by 14.63 % in the Au-gate (gate-1) and Pt-gate (gate-2) material-based Double-Gate (DG) MOSFET compared to the Silicon-based DG MOSFET. This paves the way for higher electron mobility, in turn, it can be used in highfrequency device manufacturing. The proposed material can be used in high-speed hybrid applications such as HEMTs and radiofrequency devices for long-haul communication.

A comprehensive hydrometallurgical recycling approach for the environmental impact mitigation of EoL solar cells

With the rapid increase of the installed capacity of crystalline silicon photovoltaic (PV) modules, the number of used modules that reach their End of Life (EoL) is accumulating dramatically and it is expected to pose significant environmental hazards. To solve this upcoming issue, this research investigated a comprehensive hydrometallurgical recycling process for crystalline silicon (C-Si) solar cells with regard to the problems of low element separation efficiency, inadequate component recovery rate, and deficient environmental considerations in the current recycling processes. Appropriate hydrometallurgical recovery processes were designed to recover valuable elements and entrap hazardous material lead (Pb) while properly treating wastewater from the recycling process. Nitric acid (HNO3) is an effective choice for elemental leaching from the waste, with 98.12% and 99.57% simultaneous leaching rates of silver (Ag) and aluminum (Al), respectively. The overall recovery rate of Ag was 96.13% using the hydrochloric acid (HCl) precipitation-ammonia solubilization-hydrazine process route. The purity of Ag after reduction was 99.8%. The silicon nitride (SiNx) and silicon phosphide (Si3P4) layers on the surface of the silicon wafer can be completely etched and removed by low-concentration HCl, and the product obtained is pure silicon. Most importantly, heavy metal elements such as Pb were captured to prevent potential damage to the environment and human health.

Plasma enhanced chemical vapor deposition of gallium phosphide at low temperature

This article is devoted to the formation and study of the properties of amorphous gallium phosphide layers obtained by plasma-chemical deposition at a temperature of 250 °C. The optical and structural properties of the obtained layers on fused silica and silicon substrates were investigated. The possibility of the formation of a homogeneous amorphous gallium phosphide with a smooth surface at a low temperature and low power of RF plasma was shown.

A Selective BP/Si Contact Formed by Low-Temperature Plasma-Enhanced Atomic Layer Deposition

It is shown for the first time that thin boron phosphide (BP) layers on silicon substrates can be formed by low-temperature plasma-enhanced atomic layer deposition at 250°C. Experiments demonstrated the possibility of using these BP/Si interfaces as selective hole contacts to silicon in solar cells.

Epitaxial synthesis of single-domain gallium phosphide on silicon

The aim of the work is to investigate different approaches for the growth of planar gallium phosphide layers on silicon by molecular beam epitaxy. Atomic force microscopy and reflection high energy electron diffraction were used to study surface morphology and estimate the film domain structure. Developed growth technique with the use of a low-temperature AlGaP/GaP seeding layer allowed us to achieve atomically flat pseudomorphic single-phase GaP on Si(001).

Формирование селективного контакта BP/Si с помощью низкотемпературного плазмохимического осаждения

For the first time, the possibility of forming boron phosphide layers by plasma-enhanced atomic-layer deposition at a temperature of 250 ° C has been shown. Also the possibility of their use as a selective hole contact to silicon for solar cell application has been experimentally demonstrated.

High performance quantum cascade laser frequency combs at λ ∼ 6 μm based on plasmon-enhanced dispersion compensation

We demonstrate quantum cascade laser (QCL) optical frequency combs emitting at λ ∼ 6 μm. A 5.5 μm-wide, 4.5 mm-long laser exhibits comb operation from -20 °C up to 50 °C. A maximum output power of 300 mW is achieved at 50 °C showing a robustness of the system. The laser output spectrum is ∼80 cm-1 wide at the maximum current, with a mode spacing of 0.334 cm-1, resulting in a total of 240 modes with an average power of 0.8 mW per mode. To achieve frequency comb operation, a plasmonic-waveguide approach is utilized. A thin, highly-doped indium phosphide (InP) layer is inserted in the top cladding design to compensate the positive dispersion of the system (material and waveguide). This approach can be further exploited to design QCL combs at even shorter wavelengths, down to 4 μm. Different ridge widths between 2.8 and 5.5 μm have been fabricated and characterized. All of the devices exhibit frequency comb operation. These observations demonstrate that the plasmonic-waveguide is a robust and reliable method for dispersion compensation of a semiconductor laser systems to achieve frequency comb operation.