Liquid Phase Epitaxy Technique Research Articles

Liquid-phase epitaxy and characterization of YAl3(BO3)4 thin layers coactivated by Er3+ and Yb3+

Epitaxial layers of YAl3(BO3)4 co-doped with Er3+ and Yb3+ are grown from K2Mo3O10–(Y/Yb/Er)2O3–B2O3 complex flux melt by means of liquid phase epitaxy (LPE) technique. The morphology, structure and composition of the layers are investigated. Epitaxial layers with a thickness of 110 μm were obtained on laser-quality substrates, corresponding to a growth rate of 4.6 μm per hour. The segregation coefficients for Er3+ and Yb3+ cations are close to unity. The layers exhibit hexagonal huntite-type structure (sp. gr. R32) and small unite cell misfit with respect to the substrate. Absorption and emission spectra as well as fluorescence lifetime were measured.

Physical mechanism of Zn and Te doping process of In0.145Ga0.855As0.108Sb0.892 quaternary alloys

We investigated p- and n-type In0.145Ga0.855As0.108Sb0.892 semiconductor alloys grown on GaSb (100) substrates by the liquid phase epitaxy (LPE) technique with different Zinc (Zn) and Tellerium (Te) mole fractions, respectively. Photoluminescence (PL) spectra showed a band gap narrowing effect for p-type doping and a band gap widening for n-type doping, attributed to the type of carrier concentration. The carrier concentration was determined from the band-to-band transition of the PL spectra in the range of 1.20 × 1016 to 2.80 × 1017 and 7.75 × 1016 to 1.02 × 1018 cm−3 for electrons and holes, respectively. Raman spectroscopy measurements showed the phonon modes LO (GaSb–InAs)-like and TO (GaSb–InAs)-like for both types of doping. The frequency dispersion of these modes is closely tied to the presence of native defects, such as vacancies of Ga(VGa), antisites of Ga in Sb (GaSb), and VGa–GaSb complexes. Incorporation of Zn- and Te-doping into the lattice led to a notable reduction in the full width at half maximum (FWHM) of the LO (GaSb–InAs)-like mode, as these dopants effectively diminished native defects. A detailed model is presented for the incorporation of dopants and their effect on the crystal quality. Phonon–plasmon coupling was observed through the L− mode, which overlaps with the TO (GaSb–InAs)-like mode for the carrier concentrations observed in the doped alloys. A theoretical estimation of the frequencies of the coupled modes L+ and L− was implemented as a function of the carrier concentration, based on the effective dielectric function of the quaternary compound. The L+ coupled mode shifts from the phononic to the plasmonic domain for theoretical electron concentrations ranging from ∼1017 to 5 × 1018 cm−3, while in p-type conductivity, the L+ mode remains in the phononic domain for the same range of hole concentrations. The increase in the frequency of the L+ mode with carrier concentration, such as the plasma frequency, provides another reliable method for determining carrier concentrations. This study reveals the physical mechanism of Zn an Te incorporation into InGaAsSb, which is required for the integration of p- and n-type doped quaternary alloys into optoelectronic applications. In addition, it provides a comprehensive understanding of the complex interaction mechanisms, including LO phonon–plasmon coupling modes and optical transitions, opening up new lines for exploring the electrical and structural properties of these materials.

Effects of Sc3+ admixture on luminescence and scintillation properties of Ce3+-doped Lu2Y(Al5-xScx)O12 (x = 1, 1.5, 2) garnet single-crystalline films

Effects of Sc3+ admixture on luminescence and scintillation properties were studied in Ce3+ - doped Lu2Y(Al5-xScx)O12 (x = 1, 1.5, 2) garnet single-crystalline films grown by the isothermal liquid phase epitaxy technique. The Ce3+ photoluminescence (PL) was slightly blue shifted with increasing Sc content due to a decrease in crystal field splitting of the Ce3+ 5d levels. In addition, the thermal activation energy of PL quenching, estimated from the temperature dependence of PL decay times, decreased with increasing Sc content. Lu2YAl4ScO12:Ce exhibited the highest light yield (LY) value of 420 photons/MeV at 5.5 MeV α particles along with a fast scintillation decay time constant (τe) of 17.4 ns. At room temperature, the decrease of LY value with increasing Sc content could be attributed to the thermal ionization process.

Room-temperature InAsSb pBin detectors for mid-infrared application

InAs-based compound is a direct, narrow bandgap III-V semiconductor with high carrier mobility and an attractive optoelectronic device candidate for application in the infrared region. Herein, a pBin InAsSb photodetector structure has been grown successfully by cost-effective Liquid Phase Epitaxy (LPE) technique. The introduction of high quality InAsSbP barrier can effectively reduce dark current, which leads to good room-temperature detector performances. A clear room-temperature photoresponse (1.6 A/W, corresponding to 50% external quantum efficiency) in the middle wavelength infrared (MWIR) range has been achieved. In addition, due to nearly zero valence band offset at zero bias, InAsSbP barrier blocks the electron dark current, while allowing the photogenerated holes to flow to the contact, which dramatically improved the performance of the detector without a turn-on operating bias. This self-powered device can reduce the size and weight of the system, and can be further developed towards the optoelectronic integrated nanosystems. The combination of the good room-temperature performance, self-powered design, and cost-effective fabrication suggests that this pBin InAsSb photodetector has wide application prospect in both military and civilian field.

Development of Tb1.5Gd1.5Al5O12:Ce Single-Crystalline Film Converters for WLED Using a Liquid Phase Epitaxy Growth Method

The investigation of the structural, luminescent and photoconversion properties (color coordinates, correlated color temperature, color rendering index and luminous efficacy) of the single-crystalline films of Ce3+-doped Tb1.5Gd1.5Al5O12:Ce mixed garnet with variable film thickness was performed in this work. These film converters were grown on undoped Y3Al5O12 substrates using the liquid phase epitaxy technique. When combined directly with blue LEDs that were commercially available in the market, the developed garnet film converters were responsible for producing white light. The trend line on the color coordinate diagram was obtained for the first time for the Tb1.5Gd1.5Al5O12:Ce converters with the systematic variation in film thickness in the range of 45–82 µm. Under 464 nm blue LED excitation, the investigated converters with a thickness of 55 µm resulted in an ideal white color.

Optical, luminescence and scintillation characteristics of Gd3Sc2(Al3-xGax)O12: Ce,Mg (x = 0, 1, 2) single crystalline films

Optical, luminescence and scintillation characteristics of Ce3+ - doped Gd3Sc2(Al3-xGax)O12 (x = 0, 1, 2) single crystalline films fabricated by the liquid phase epitaxy (LPE) technique are investigated. A blue shift of the photo- and radio-luminescence spectra is observed as Ga content increased due to a decrease in crystal field splitting of the Ce3+ 5d levels. Temperature-dependent characteristics of radioluminescence (RL) intensity and photoluminescence (PL) decay time are investigated. At room temperature, the decrease of PL- & RL- intensity and PL decay time with increasing Ga content can be explained by thermal ionization of the Ce3+ 5d1 excited state. Gd3Sc2Al2GaO12:Ce exhibits the highest light yield (LYα) value of 1010 ph/MeV along with fast scintillation decay time of 12 ns (27%) + 52 ns (73%) under excitation with 5.5 MeV α – particles. Shortening of scintillation decay time with a decrease of the LY value is also obtained in Mg2+-codoped samples.

Importance of liquid phase epitaxy on achieving near-lattice-matched growth of In0.145Ga0.855As0.132Sb0.868 layers on GaSb(100) substrates

We report the growth of In0.145Ga0.855As0.132Sb0.868 layers on GaSb(100) substrates by the liquid phase epitaxy (LPE) technique using the ramp-cooling method. We achieved a near-lattice-matched epitaxial growth with a lattice mismatch of between the quaternary layer and GaSb(100) substrate due to optimal growth parameters. Aberration-corrected scanning transmission electron microscope (AC-STEM) confirmed the high crystalline quality of the quaternary layer and the low lattice mismatch in the heterostructure, without the presence of linear or planar defects. Also, the Secondary Ion Mass Spectrometry (SIMS) technique evidenced a uniform distribution of the atomic elements along the quaternary layer and an abrupt interface between the In0.145Ga0.855As0.132Sb0.868 layer and the GaSb substrate. Plasmon-phonon interactions were observed by Raman spectroscopy indicating that the crystalline quality increases at greater depth in the sample with respect to the surface. The quaternary layer presented a uniform and flat morphology, and luminescence emission attributed to the recombination of bound exciton states at 641 meV. The structural, chemical, and optical properties of the In0.145Ga0.855As0.132Sb0.868 layer demonstrated that it could be auspicious material for infrared range optoelectronic applications. Likewise, the LPE technique successfully shows that it should be used to grow near-lattice-matched heterostructures.

Strain induced anisotropy in liquid phase epitaxy grown nickel ferrite on magnesium gallate substrates

This work focuses on the nature of magnetic anisotropy in 2.5–16 micron thick films of nickel ferrite (NFO) grown by liquid phase epitaxy (LPE). The technique, ideal for rapid growth of epitaxial oxide films, was utilized for films on (100) and (110) substrates of magnesium gallate (MGO). The motivation was to investigate the dependence of the growth induced anisotropy field on film thickness since submicron films of NFO were reported to show a very high anisotropy. The films grown at 850–875 C and subsequently annealed at 1000 C were found to be epitaxial, with the out-of-plane lattice constant showing unanticipated decrease with increasing film thickness and the estimated in-plane lattice constant increasing with the film thickness. The uniaxial anisotropy field Hσ, estimated from X-ray diffraction data, ranged from 2.8–7.7 kOe with the films on (100) MGO having a higher Hσ value than for the films on (110) MGO. Ferromagnetic resonance (FMR) measurements for in-plane and out-of-plane static magnetic field were utilized to determine both the magnetocrystalline the anisotropy field H4 and the uniaxial anisotropy field Ha. Values of H4 range from −0.24 to −0.86 kOe. The uniaxial anisotropy field Ha was an order of magnitude smaller than Hσ and it decreased with increasing film thickness for NFO films on (100) MGO, but Ha increased with film thickness for films on (110) MGO substrates. These observations indicate that the origin of the induced anisotropy could be attributed to several factors including (i) strain due to mismatch in the film-substrate lattice constants, (ii) possible variations in the bond lengths and bond angles in NFO during the growth process, and (iii) the strain arising from mismatch in the thermal expansion coefficients of the film and the substrate due to the high growth and annealing temperatures involved in the LPE technique. The LPE films of NFO on MGO substrates studied in this work are of interest for use in high frequency devices.

Novel Negative Capacitance Appeared in all Frequencies in Au/AlCu/SiO2/p-Si/Al Structure

AbstractTo the best of our knowledge. The current work shows that negative capacitance exists at all frequencies, contrary to what is claimed in the literature, which states that negative capacitance only exists at high or low frequencies. In this paper, Au/AlCu/SiO2/p-Si/Al structure was epitaxial grown by the liquid phase epitaxial growth technique. The structural characterization was studied using an X-ray diffraction pattern. The capacitance and conductance behavior was studied using I-V and C-V measurements at various temperatures, voltages, and frequencies. Negative capacitance appears at all frequencies ranging from low to high; moreover, capacitance has both positive and negative values at all frequencies, while the conductance has positive values only in all frequencies. The current-voltage characterization was used to investigation the ideality factor, barrier height, and series resistance. The barrier height and Richard constant were estimated, through investigating the current conduction mechanism of Au/AlCu/SiO2/p-Si/Al.

Plasma-assisted vapor liquid phase epitaxial growth of dilute GaSbxN1−x and GaBiyN1−y alloys: Confirmation of band gap reduction discontinuity

Single crystal quality films of dilute $\mathrm{Ga}{\mathrm{Sb}}_{x}{\mathrm{N}}_{1\ensuremath{-}x}$ and $\mathrm{Ga}{\mathrm{Bi}}_{y}{\mathrm{N}}_{1\ensuremath{-}y}$ alloys were synthesized through a plasma-assisted vapor liquid phase epitaxy technique in which nitrogen radicals, antimony, and bismuth species diffuse through molten gallium and form alloys at the substrate. Incorporation fractions $x$ up to 0.009 (three samples), and $y$ up to 0.011 (two samples) were achieved. Morphology and photoluminescence characteristics as well as x-ray spectra were evaluated confirming the alloys possess gallium nitride wurtzite structure but with a slightly higher lattice parameter as determined with differences of hundredths of degrees in the diffraction peak position of plane (002). UV-Vis spectrometry measurements of the alloys also resemble those of pure gallium nitride, indicating dilute anion substitution at the levels reported in this study are not sufficient to promote significant changes in the band gap versus host material, gallium nitride. First-principles density functional theory incorporating the local-density approximation/generalize gradient approximation+U formalism also reveals that relatively small concentration of Sb impurities is not sufficient to achieve a significant narrowing of gallium nitride band gap.

In situ observations of the dissolution of an AlN film into liquid Al using a high-temperature microscope

This report describes the implementation of an original liquid-phase epitaxy (LPE) technique using a Ga–Al solution. An N-polar AlN thin film prepared using a sapphire nitridation method was employed as the template for the LPE growth process. The growth behavior depended on attaining a competitive balance of the polarity inversion and the dissolution reaction of the AlN thin film. Therefore, to improve the overall LPE process, it was crucial to understand exactly when and how the AlN thin film dissolved in the solution. This study investigated the dissolution of the N-polar AlN thin film into liquid Al and the resulting AlN growth through in situ observation experiments. The AlN thin film dissolved at a lower temperature than the required temperature for AlN growth. On the basis of these findings, we designed an LPE growth process to obtain a homogeneous AlN layer without the dissolution of the N-polar AlN thin film. Ultimately, a homogeneous AlN layer was successfully formed on the nitrided sapphire substrate using Ga-60mol%Al at 1300 °C for 5 h.

Si−doped In0.145Ga0.855As0.123Sb0.877: A novel p−type quaternary alloy with high crystalline quality

Antimonide−based p−n junctions are particularly attractive for a wide variety of optoelectronic applications in the near and mid-infrared wavelength range. In this work, novel p−type Si−doped In0.145Ga0.855As0.123Sb0.877 epitaxial layers were grown on GaSb(100) substrates by Liquid Phase Epitaxy (LPE) technique. The XPS spectra measured on Si−doped In0.145Ga0.855As0.123Sb0.877 layers indicate that Si atoms behave as acceptors. The analysis of the surface depletion region and its relationship with phonon−plasmon L_ coupling were investigated using Raman spectroscopy, giving an acceptor concentration of NA ∼ 5.8 × 1017 cm−3 for a depletion region thickness of d ∼ 9.4 nm. Low temperature photoluminiscence (PL) spectrum for the Si−doped In0.145Ga0.855As0.123Sb0.877 layers showed a bound excitonic emission peak associated to neutral Sb acceptors, with an activation energy of ∼10meV and a donor−acceptor transition. It was observed that the Si doping reduces the excitonic emission intensity and increases the donor−acceptor pair recombination intensity.

Microwave Dielectric Spectroscopy Study of MOF Clathrates in Volatile Organic Compounds Detection

Metal-organic frameworks (MOFs) are porous defective crystalline compounds that can form clathrates. In principle, the defects in these materials behave like the defects in other metal oxides such as ZnO, which are used as metal-oxide semiconductor gas sensors. Traditional chemical resistivity based MOS gas sensors require electrical contact to the sensing materials. These contacts are imperfect and will subsequently introduce errors into the measurements. In this paper, we will demonstrate the feasibility of using contactless broadband dielectric spectroscopy (BDS)-based metrology in gas monitoring that avoids distortions in the reported resistivity values due to probe use, and parasitic errors (i.e., tool-measurand interactions). Specifically, we will show how radio frequency (RF) propagation characteristics can be applied to study discrete processes involved in HKUST-1 SURMOF (Surface Anchored Metal-Organic Framework) sensing and detection of gases and volatile organic compounds (VOCs). HKUST-1 MOF films, also known as Cu3(BTC)2 (BTC: benzenetricarboxylicacid), consist of metal ions connected by organic ligands, forming highly ordered porous structures and are commonly grown by a layer-by-layer (LBL) liquid phase epitaxy (LPE) technique. We intend to use BDS to investigate the initial oxidization of MOF gas sensing material in air and nitrogen at temperatures below 200 °C, and to show that the technique yields new mechanistic insights that are unobtainable with the conventional resistance-based measurements.

Investigation of Aging Effects in Thermoelectric Surface Anchored Metal-Organic-Framework (SURMOFs) Films Using Nanoindentation

Thin films of Metal-organic-framework (MOF) materials are deposited using a layer-by-layer (LBL) liquid phase epitaxy (LPE) technique. The highly oriented Surface Anchored Metal-Organic Framework (SURMOFs) of Cu3(BTC)2 (BTC: benzenetricarboxylicacid), known as HKUST-1 MOF were grown on Si (100) substrates. MOF materials are designed scaffold-like compounds that consist of metal ions connected by organic ligands, forming highly ordered porous structures. MOF materials found their way to various applications including gas storage due to high storage capacity and device applications in thermoelectrics and microelectronics [1,2]. The thermoelectric application potential of HKUST-1 SURMOF films is based on their large Seebeck coefficient and the premise that the electrical properties of the otherwise insulating MOF films can be custom tailored by loading the porous MOF structure with metal clusters. For modulating the electrical conductivity of MOF films the most effective method is to infiltrate guest molecules inside the porous framework to transport ions, and hence to modulate the electrical properties of the host framework. With nanoindentation testing of the fresh and aged pristine and TCNQ loaded samples, we demonstrate that aging effects impacted the mechanical properties of the films. The aged pristine samples hardness is 0.29 GPA as compared to the fresh as-grown pristine sample of 0.16 GPA at depth of indentation/film thickness (Similarly for the TCNQ loaded samples the hardness of the aged and fresh samples is 0.22 and 0.05 GPA respectively. As hybrid organic-inorganic thermoelectric materials HKUST-1 SURMOF films are subject to aging effects. References Mazure and A.J. Auberton-Herve, Proc. of 35th European Solid-State Device Research Conf. ESSDERC, p. 29 (2005)A. Langdo, M. T. Currie, Z.-Y. Cheng, J.G. Fiorenza, M. Erdtmann, G. Braithwaite, C.W. Leitz, C.J. Vineis, J. A. Carlin, A. Lochtefeld, M. T. Bulsara, I. Lauer, D.A. Antoniadis, M. Somerville, Solid-State Electronics, 48 , 1357 (2004). Figure 1

DEPOSITION OF Al/SnAl OHMIC CONTACT ON SILICON FROM A LIQUID PHASE

Background. Single- and multi-layer metal films are widely utilized in modern electronics and optoelectronics as ohmic contacts. As a rule, the films are deposited by thermal evaporation, ion sputtering and chemical vapour deposition. However the methods of deposition from a liquid phase are the most simple and cost-effective. Thus the ohmic contact deposition by these methods is still an actual problem. Objective. The purpose of the paper is to study the possibility of deposition of multi-layer ohmic metal films over a semiconductor wafer surface from a liquid phase, particularly by scanning liquid phase epitaxy technique. Methods. In this work we considered the influence of a long-term temperature gradient at the interface metallic solution-melt – semiconductor wafer on the possibility of deposition of multi-layer ohmic metal films on the semiconductor wafer surface during segmental contact between the solution-melt and the wafer. For this purpose we carried out the simulation of heat transport process, wafer wetting process as well as the process of wafer cleansing off the solution-melt taking into account capillary phenomena in the mask openings using the method of scanning liquid phase epitaxy. For experimental confirmation of adequacy of the model proposed we carried out the deposition of Al/SnAl layer on silicon wafer in the above mentioned conditions. Results. We have deposited the contact layer Al/SnAl on the surface of silicon wafer from Al-Sn solution-melt by scanning liquid phase epitaxy technique using supplementary heater for the wafer and mask installed in the apparatus. The contact layer is made as three identical pads located at different distance one from each other. By the analysis of current-voltage characteristic we determined that the metallic film contact with the semiconductor is a non-rectifying, i.e. ohmic contact. The specific contact resistance was determined by the Transmission Line Method using linear configuration of the contact pads (LTLM). Its value was 7.2∙10-4 Ohm·cm2. Conclusions. The principal possibility of obtaining of multi-layer ohmic contacts to the semiconductor by scanning liquid phase epitaxy technique in conditions of segmental contact between the solution-melt and the wafer as well as long-term gradient at the contact interface was shown. The conditions were realized by using extra heating of the wafer back side and the high-temperature mask through which the solution-melt contacted the wafer.

Crystallization and Investigation of the Structural and Optical Properties of Ce3+-Doped Y3−xCaxAl5−ySiyO12 Single Crystalline Film Phosphors

This work is devoted to the crystallization and investigation of the optical properties of single crystalline films (SCFs) of Ce3+-doped Y3−xCaxAl5−ySiyO12 garnet, where the content of Ca2+ and Si4+ cations varied in the x = 0.13–0.52 and y = 0.065–0.5 ranges, respectively. The SCF samples were grown using the liquid phase epitaxy technique onto Y3Al5O12 substrates from the melt solution with equimolar Ca and Si content using PbO-B2O3 flux. However, the Ca and Si concentration in Y3−xCax Al5−ySiyO12:Ce SCFs is not equal: the Ca2+ content was systematically larger than that of Si4+, and the Ca2+ excess is compensated for by the Ce4+ ion formation. The absorption, scintillation, and luminescent properties of Y3−xCaxAl5−ySiyO12:Ce SCFs with different Ca/Si concentrations were investigated and compared with the sample of YAG:Ce SCF. Due to the creation of Ce4+ ions, the as-grown Y3−xCaxAl5−ySiyO12:Ce SCFs show relatively low light yield (LY) under α–particle excitation but a fast scintillation response with a decay time in the ns range. After SCF annealing in the reducing (N2 + H2) atmosphere at T > 1000 °C, the recharging of Ce4+→Ce3+ ions occurs. Furthermore, the samples annealed at 1300 °C SCF possess an LY of about 40% in comparison with the reference YAG:Ce SCF and scintillation decay kinetics much closer to that of the SCF counterpart. Due to Ca2+ and Si4+ alloying, the Ce3+ emission spectra in Y3−xCaxAl5−ySiyO12 SCFs are extended to the red range in comparison with the spectra of YAG:Ce SCF. Such an extension is caused by the Ce3+ multicenter formation at the substitutions of both Y3+ and Ca2+ dodecahedral positions in the hosts of these mixed garnets.

Toward Exotic Silicon Doping with a Low Thermal Budget and Flexible Profile Control by Liquid-Phase Epitaxy.

We investigate semiconductor p-n junction formation by liquid-phase epitaxy (LPE) using metallic pastes incorporating traditional and nontraditional dopants. The LPE technique enables us to control the shape of doping profiles with a low thermal budget through the choice of solvent, total amount of solvent deposited, and process temperature. We focus here on the Al-B, Zn-P, and Sn-Ga chemistries to dope silicon regions using the chemicophysical properties of a low-eutectic-temperature metallic solvent acting as a matrix for the dissolution of a high concentration of a dopant. Additionally, we developed a capping method enabling doping across a large surface area wafer with a tunable thickness well below 1 μm without film dewetting. In good agreement with thermodynamic simulation of the LPE process, we demonstrate B- and Al-doped regions with a sheet resistance ranging from less than 10 to 300 Ω/sq between 650 and 800 °C, which is significantly lower than the typical temperatures of gas-phase doping processes. Comprehensive electrical simulations suggest that LPE p-n junctions with a low carrier recombination activity can be fabricated via the reduction of surface doping concentration and improved surface recombination velocity. Our investigation of exotic LPE chemistries suggests that emitter saturation currents below 50 fA/cm2 could be achieved at doping concentrations relevant to solar cells.

Dislocation evolution along the growth direction of 2-inch GaN crystal grown by Na-flux LPE

2-inch GaN crystals with 1170 μm thickness were successfully grown on MOCVD-GaN thin film seed by Na flux liquid phase epitaxy (Na-flux LPE) technique. X-ray diffraction analysis confirmed that the structure of as-grown GaN crystals was wurtzite. The dislocation etching pit morphologies of GaN crystals at different growth thicknesses were observed by SEM using chemical etching and the dislocation densities were measured. The dislocation density decreased as the growth thickness increased, which could decrease to 105 cm−2 order at the thickness of 870 μm, comparing to about 108 cm−2 of original MOCVD-GaN thin film seed. The mechanism of dislocation density reduction was discussed.

Dynamic Magnonic Crystals for Measuring the Dispersion of Bulk Magnetostatic Spin Waves Caused by Magnetic Anisotropy in YIG Films

A dynamic magnonic crystal created by a surface acoustic wave that propagates in a GGG–YIG structure (gallium–gadolinium garnet–yttrium–iron garnet) is used to measure the dispersion of bulk magnetostatic waves due to the magnetic anisotropy in the YIG film. Such waves, which are called anisotropic-dipole magnetostatic waves (ADMSWs), can propagate together with surface spin waves in YIG films that are placed in a tangential magnetic field. It is shown experimentally that ADMSWs with a positive dispersion law occur in films that are grown by the liquid-phase epitaxy technique and not subjected to additional processing,. In the films that were subjected to additional processing the ADMSW dispersion law is negative when applying a piezoelectric zinc oxide film or bombarded with boron ions.

Effect of the Sb content and the [formula omitted] and [formula omitted] substrates on the physical and chemical properties of InSbxAs1-x alloys for mid-infrared applications: Analysis of surface, bulk and interface

Antimonide-based family holds the potential for developing a new generation of mid-infrared applications. Here, we report on the growth of InSbxAs1-x alloys on n− and p−type GaSb(100) substrates varying the Sb mole fraction (x), using the liquid phase epitaxy (LPE) technique. We show that the ternary alloy grown on the n−type GaSb substrate presents higher crystalline quality, thermal diffusivity and interfacial thermal conductivity, as compared to the one grown on pin equation type GaSb substrates which decrease as the Sb mole fraction (x) in the layer increases. Our results demonstrate that the InSbxAs1-x/n−GaSb heterostructure reaches the thermal equilibrium faster than the InSbxAs1-x/p−GaSb structure, with lower roughness, strain, as well as a better chemical abruptness at substrate-layer interface. We also find that the growth mechanism of the InSbxAs1-x alloy is constituted by In−As and In−Sb bonds. Furthermore, the Raman scattering spectra measured at different layer depths evidence that the crystalline quality improves with depth and allow the identification of an intrinsic depletion region. Since the InSbxAs1-x alloy presents a long-range atomic order grown on both n− and p−type GaSb substrates, the phonon-plasmon coupled L− and L+ modes are observed, and from the L+ coupled mode, we obtain the intrinsic carrier concentration and its variation with the Sb mole fraction. Therefore, this work provides important guidance on the structural, thermal, and chemical properties of the surface, bulk and interface of InSbxAs1-x alloys, that should be considered to improve the performance of future devices, such as better heat dissipation.$