Growth and characteristics of InAsSb epilayers with a cutoff wavelength of 4.8 μm prepared by one-step liquid phase epitaxy

InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.

Liquid phase epitaxy magnetic garnet films and their applications

Liquid phase epitaxy （LPE） is a mature technology. Early experiments on single magnetic crystal films fabricated by LPE were focused mainly on thick films for microwave and magneto-optical devices. The LPE is an excellent way to make a thick film, low damping magnetic garnet film and high-quality magneto-optical material. Today, the principal challenge in the applied material is to create sub-micrometer devices by using modern photolithography technique. Until now the magnetic garnet films fabricated by LPE still show the best quality even on a nanoscale （about 100 nm）, which was considered to be impossible for LPE method.

Al_xGa_(1-x)As/GaAs Solar Cell Grown by Multi-substrate Liquid Phase Epitaxy

A novel horizontal push-pull multi-substrate epitaxy boat with three separate cells is introduced in this article, with which multi-substrate LPE processing is feasible in horizontal LPE furnace. The processes of LPE AlxGa1-x)As/ GaAs solar cells are studied and the efficiency of the solar cells achieved 19.8% （AMO, 25℃, 120 mW/cm2）.

SOLUBILITY CHARACTERISTICS OF GaAs IN Bi AND THEIR PHASE DIAGRAM

A modified liquid phase epitaxy apparatus for semiconductor materials was used to measure the solubility of GaAs in Bi.Two phase diagrams rich in Bi under H_2 and N_2 atmospheres were obtained according to the results of measurement.A new phenomenon,in which the parameter Q value(quantity of GaAs dissolved in Bi in fixed time/saturation quantitu,of GaAs in Bi)was different from each other at various temperatures and there existed a maxi- mum Q value at definite temperature,was observed.This phenomenon may be regarded as a common feature of a simple binary metallic system which has the phase diagram similar to that of Bi-GaAs.The difference observed from the dependence of Q values on temperature in both H_2 and N_2 atmospheres was discussed.

Liquid-phase epitaxy of metal organic framework thin films

Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically adhesive to a(functionalized) substrate and,in an ideal case,exhibiting low roughness and high homogeneity.Various innovative approaches have been developed for MOF thin film fabrication.Among these advanced materials,surface-attached metal-organic frameworks(SURMOFs) are an important class of MOF films.SURMOFs,fabricated in a step-by-step liquid phase epitaxial(LPE) fashion by alternating deposition of metal and organic linker precursors on a functionalized substrate,for example,thiolate-based self-assembled monolayers(SAMs),have already exhibited their utility in both research and potential applications.SURMOFs combine surface science and the chemistry of MOFs,possessing the following unique advantages that cannot be accessed through other methods:(i) precisely controlling thickness,roughness and homogeneity as well as growth orientation,(ii) studying of MOF growth mechanism,(iii) modifying/tailoring MOFs' structures during the SURMOF growth and thus creating customizable properties,and(iv) existing in the form of thin film/membrane for direct applications,for example,as sensors.This review discusses the oriented and crystalline SURMOFs fabricated by LPE approach,covering their preparation,growth mechanism,and characterization methodology as well as applications based upon the most newly updated knowledge.

Ⅲ-Ⅴ semiconductor nanocrystal formation in silicon nanowires via liquid-phase epitaxy

Direct integration of high-mobility III-V compound semiconductors with existing Si-based complementary metal-oxide-semiconductor （CMOS） processing platforms presents the main challenge to increasing the CMOS performance and the scaling trend. Silicon hetero-nanowires with integrated III-V segments are one of the most promising candidates for advanced nano-optoelectronics, as first demonstrated using molecular beam epitaxy techniques. Here we demonstrate a novel route for InAs/Si hybrid nanowire fabrication via millisecond range liquid-phase epitaxy regrowth using sequential ion beam implantation and flash-lamp annealing. We show that such highly mismatched systems can be monolithically integrated within a single nanowire. Optical and microstructural investigations confirm the high quality hetero-nanowire fabrication coupled with the formation of atomically sharp interfaces between Si and InAs segments. Such hybrid systems open new routes for future high-speed and multifunctional nanoelectronic devices on a single chip.

Characteristics of n-InAs/p-InAsSb heterojunctions with a cutoff wavelength of 4.8 μm

n-InAs/p-InAsSb heterojunctions with a cutoff wavelength of 4.8 μm were successfully grown by one-step liquid phase epitaxy （LPE） tech-nology. Scanning electron microscopy （SEM） images and X-ray diffraction （XRD） patterns showed the mirror smooth surface, flat interface, and good crystalline quality of the heterojunctions. Fourier transform infrared （FTIR） transmittance spectra exhibited that the cutoff wave-lengths of InAsSb epilayers reach 4.8 μm. The standard current-voltage （I-V） characteristics with a high differential-resistance-area-product at zero bias （R0A） of 1.02×10-1 Ωcm2 at room temperature indicate that the fine p-n junctions have been obtained.

Bismuth-Substituted Yttrium Iron Garnet Film/Crystal Composite for Faraday Rotators

The novel bismuth-substituted rare earth iron garnet films were grown by the modified liquid phase epitaxy (LPE) technique for use as a 45° faraday rotator in optical isolators. First,single crystals of Y_3Fe_5O_(12) (YIG),with a lattice constant of 1.2378 nm,were grown by means of the Czochralski method. Using YIG instead of the conventional non-magnetic garnet of Gd_3Ga_5O_(12) (GGG) as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi_2O_3-B_2O_3 fluxes. The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite were investigated using X-ray diffraction (XRD),electron probe microanalysis (EPMA),vibrating sample magnetometry (VMS) and near-infrared transmission spectrometry. The saturation magnetization 4π M _s was estimated to be about 1200 G. The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry (RAE) with the wavelength varied from 800 to 1700 nm. The resultant Bi_(0.37)Yb_(2.63)Fe_5O_(12) LPE film/YIG crystal composite shows an increased Faraday rotation coefficient due to doping Bi (3+) ions on the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,can achieved of 21.5 and 30.2 °/dB at 1300 and 1550 nm wavelengths respectively at room temperature. Since Yb (3+) ions and Y (3+) ions provide the opposite contributes to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients are reduced to 0.06%/nm and 0 007 °·℃ (-1) at 1550 nm wavelength,respectively.

Novel Bi-substituted Yttrium Iron Garnet Film/Crystal Composite for Magneto-optical Applications

The novel Bi-substituted rare-earth iron garnet films were grown by the modified liquid phase epitaxy （LPE） technique for use as a 45° Faraday rotator in optical isolators.First,single crystals of Y3Fe5O12 （YIG）,with a lattice constant of 1.237 8 nm,were grown by means of the Czochralski method.Using the seed crystal of YIG instead of the conventional non-magnetic garnet of Gd3Ga5O12 （GGG） as a substrate,a film of BiYbIG was grown by means of the LPE method from Bi2O3-B2O3 fluxes.The structural,magnetic and magneto-optical properties of BiYbIG LPE film/YIG crystal composite have been investigated using directional X-ray diffraction （XRD）,electron probe microanalysis （EPMA）,vibrating sample magnetometer （VMS） and near-infrared transmission spectrometry.The saturation magnetization 4πMs has been estimated to be about 1.2×106 A/m.The Faraday rotation spectrum was measured by the method of rotating analyzer ellipsometry （RAE） with the wavelength varied from 800 nm to 1 700 nm.The resultant Bi0.37Yb2.63Fe5O12 LPE film/YIG crystal composite showed an increased Faraday rotation coefficient due to doping Bi3+ ions into the dodecahedral sites of the magnetic garnet without increasing absorption loss,therefore a good magneto-optic figure of merit,defined by the ratio of Faraday rotation and optical absorption loss,has been achieved of 21.5 and 30.2 （°）/dB at 1 300 and 1 550 nm wavelengths respectively and room temperature. Since Yb3+ and Y3+ ions provide the opposite contribution to the wideband and temperature characteristics of Faraday rotation,the values of Faraday rotation wavelength and temperature coefficients were reduced to 0.06 %/nm and 0.007 （°）/℃ at 1 550 nm wavelength, respectively.

Organometallic perovskite single crystals grown on lattice-matched substrate for photodetection

In this work,we demonstrate that an organometallic perovskite(OP)single crystal for effective photodetection can be grown on a gold(Au)-decorated substrate using liquid phase epitaxy.The covered gold could both control the shape of the epitaxial layer and act as its electrodes.An MAPbCl3 single crystal and an MAPbBr1.5Cl1.5 single crystal were used as the substrate and the epitaxial layer,respectively.The device,with an Au-perovskite-Au structure,can be fully characterized.Due to the high-quality epitaxial layer,the maximum external quantum efficiency(EQE)value is over 60%under the voltage of
20 V.In addition,the response speed can reach 200 and 500 ns(ns)rise and fall,respectively.Our work provides an effective and promising method to fabricate efficient perovskite-based photodetectors.

Photonic crystals constructed by isostructural metal-organic framework films

Metal-organic framework(MOF)-on-MOF structure allows stacking various types of MOFs with different lattice constants for molecule sieving or filtering.However,the multilayered MOFs-based optical devices have incoherent interference due to the lattice-mismatch at the interface and refractive index(RI)indifference.This paper reports isostructural MOFs-based photonic crystals(PCs)designed by stacking Bragg bilayers of lattice-matched MOFs thin films through a layer-by-layer assembly method.Colloidal nanoparticles(NPs)were homogenously encapsulated in some layers of the MOFs(HKUST-1@NPs)to tune their intrinsic RI during the spraying coating process.The isostructural MOFs-based PCs were constructed on a large scale by sequentially spraying coating the low RI layer of HKUST-1 and high RI layer of HKUST-1@NPs to form the desired number of Bragg bilayers.X-ray photoelectron spectroscopy(XPS)depth profiling proved the Bragg bilayers and the homogenous encapsulation of nanomaterials in certain layers of MOFs.Bandwidth of the PCs was tailored by the thickness and RI of the Bragg bilayers,which had a great consistent with finite difference time domain(FDTD)simulation.Importantly,reflectivity of the isostructural MOFs-based PCs was up to 96%.We demonstrated high detection sensitivity for chemical sensing on the PCs,which could be advanced by encapsulating different types of nanomaterials and designing wide-band isostructural MOFs-based PCs.

Geometric Evolution Laws for Thin Crystalline Films: Modeling and Numerics

Geometrical evolution laws are widely used in continuum modeling of surface and interface motion in materials science.In this article,we first give a brief review of various kinds of geometrical evolution laws and their variational derivations,with an emphasis on strong anisotropy.We then survey some of the finite element based numerical methods for simulating the motion of interfaces focusing on the field of thin film growth.We discuss the finite element method applied to front-tracking,phase-field and level-set methods.We describe various applications of these geometrical evolution laws to materials science problems,and in particular,the growth and morphologies of thin crystalline films.

Steady-state solution growth of microcrystalline silicon on nanocrystalline seed layers on glass

The growth of polycrystalline silicon layers on glass from tin solutions at low temperatures is presented.This approach is based on the steady-state solution growth of Si crystallites on nanocrystalline seed layers, which are prepared in a preceding process step. Scanning electron microscopy and atomic force microscopy investigations reveal details about the seed layer surfaces, which consist of small hillocks, as well as about Sn inclusions and gaps along the glass substrate after solution growth. The successful growth of continuous microcrystalline Si layers with grain sizes up to several ten micrometers shows the feasibility of the process and makes it interesting for photovoltaics.