Indium Selenide Telluride (InSeTe) ternary compounds, including InSe-InTe alloys, are van der Waals semiconductors with tunable electronic and optical properties, making them attractive candidates for next-generation optoelectronic devices. However, achieving controlled growth across the full composition range of the InSe1-xTex system remains challenging due to competing phase transitions and the sensitivity of stoichiometry to variations in composition. In this study, we demonstrate the molecular beam epitaxial growth of InSe1-xTex (0 < x < 1) thin films using an indium precursor layer on amorphous SiO2 substrates. By modulating the Se and Te flux ratios, we precisely controlled the composition across three distinct groups within the InSe-InTe system. Structural analysis by X-ray diffraction reveals that for x <0.6, the films retain a hexagonal InSe base, accompanied by a systematic shift of the diffraction peaks to lower angles as the Te content increases. When the Te fraction ranges between 0.6 and 0.8, mixed phases are observed. Furthermore, for x > 0.8, the tetragonal InTe structure becomes the dominant phase. Surface characterization by scanning electron microscopy shows irregular morphologies associated with the precursor-assisted growth pathway, reflecting near-equilibrium nucleation dynamics. These results provide a comprehensive understanding of the composition-phase transition-crystallinity relationships in InSe1-xTex compounds.

In this work, we present a novel avalanche photodiode (APD) that utilizes the Si_1-xSn_x -on-silicon (SiSn-on-Si) platform to enable short-wave infrared (SWIR) operation. This work reports the first proof of the Si_1-xSn_x alloy-based APD. Here, we propose two device structures—p+-i-p-i-n+ (device D1) and n+-i-n-i-p+ (device D2)—and we use COMSOL Multiphysics to analyze their performance. With the insertion of Sn into the Si_1-xSn_x alloy, the bandgap energy decreases, and the detection wavelength is redshifted toward a longer wavelength. As a result, this work presents the breakthrough of Si-based detectors, demonstrating significant advancements in the field. Moreover, the high absorption coefficient of the Si_1-xSn_x alloy over pure Si results in high responsivity. The separate absorption, charge, and multiplication (SACM) device structure allows for a substantial performance improvement, with device D1 achieving a high multiplication gain of over 77 and device D2 achieving a multiplication gain of over 80 at a wavelength of 1310 nm and a temperature of 300 K. Our proposed SiSn-on-Si APD shows a significant reduction in excess noise factor compared to the In0.52Al0.48As device. In addition, when compared to previously reported Si/Ge APDs, the SiSn-on-Si APD demonstrates superior performance in terms of gain, responsivity, and the low bias voltage required for operation. These findings, using the cost-effective SiSn-on-Si platform, provide a pathway for the future development of high-performance Si-based APDs for use in the SWIR bands.

The integration of renewable energy sources and the increasing demand for efficient power delivery have highlighted the need for advanced protection devices in power systems. Among these devices, Superconducting Resistive Fault Current Limiters (SRFCLs) have emerged as a promising solution to mitigate the impact of fault currents. This research focuses on the performance and analysis of SRFCLs within power systems, evaluating their ability to enhance system reliability and prevent damage to critical components during fault conditions. The SRFCLS investigate the fault current limiting technologies and offer a valuable insight for power system planners, operators, and researchers. The results emphasize the potential of SRFCLs in enhancing the reliability and performance of power systems, ultimately fostering a more resilient and sustainable electrical grid.

This study was meticulously conducted, delving into the epitaxial growth of nanothin beta-In2Se3 films on sapphire (0001) using molecular beam epitaxy. The growth temperature was carefully set at 480 degrees C, and the selenium to indium flux ratio (R-Se/In) was systematically varied from 1 to 100. The phase transformation from gamma-In2Se3 to beta-In2Se3 was precisely controlled by manipulating the R-Se/In and confirmed through Raman scattering measurements and synchrotron-based grazing-incidence wide-angle X-ray scattering. The surface morphology for various R-Se/In of In2Se3 was analyzed by atomic force microscopy (AFM). The lowest surface roughness is around 0.58 nm, which is achieved under the R-Se/In = 60 growth condition. The nanothin beta-In2Se3 film with a layer-by-layer atomic arrangement was verified by high-resolution transmission electron microscopy. According to the experimental results, the growth dynamics of In2Se3 are proposed to be step-flow growth and horizontal growth under R-Se/In 45 and 60 conditions, respectively. This research underscores the control of the growth mechanism by Se/In flux and its role in facilitating the In2Se3 epitaxy for integration in the development of 2D-materials-based future electronic devices.

A two-dimensional (2D) material known as indium selenide (InSe) is widely considered a promising layered semiconductor with potential applications in electronics and optoelectronics. However, the single phase of InSe is still a challenge due to the close formation energy of InSe and In 2 Se 3 . In this study, we demonstrate a novel growth method for 2D InSe with an indium precursor layer by molecular beam epitaxy. Indium pre-deposited on substrate at room temperature followed by growth of InSe at 550°C can overcome the problem of stoichiometry control and can be applied on amorphous substrate with high quality. According to Raman scattering spectra, X-ray diffraction, and high-resolution transmission electron microscopy results, we find that 2D InSe phase can be facile formed under both indium-rich and -poor conditions. The pre-deposited indium precursor effectively induces replacement with subsequent Se and In atoms to form the InSe phase while suppressing the In 2 Se 3 phase. Additionally, this single phase InSe is stable in the atmosphere, exhibiting superior electronic properties even after over 100 days exposure. Recently, this method has been successfully applied to a flexible substrate, such as aluminum foil, resulting in reliable InSe quality. Our results demonstrate an innovative and forward-looking approach to developing 2D InSe material.

Single-phase two-dimensional (2D) indium monoselenide (γ-InSe) film is successfully grown via solid phase epitaxy in the molecular beam epitaxy (MBE) system. Having high electron mobility and high photoresponsivity, ultrathin 2D γ-InSe semiconductors are attractive for future field-effect transistor and optoelectronic devices. However, growing single-phase γ-InSe film is a challenge due to the polymorphic nature of indium selenide (γ-InSe, α-In2Se3, β-In2Se3, γ-In2Se3, etc.). In this work, the 2D α-In2Se3 film was first grown on a sapphire substrate by MBE. Then, the high In/Se ratio sources were deposited on the α-In2Se3 surface, and an γ-InSe crystal emerged via solid-phase epitaxy. After 50 min of deposition, the initially 2D α-In2Se3 phase was also transformed into a 2D γ-InSe crystal. The phase transition from 2D α-In2Se3 to γ-InSe was confirmed by Raman, XRD, and TEM analysis. The structural ordering of 2D γ-InSe film was characterized by synchrotron-based grazing-incidence wide-angle X-ray scattering (GIWAXS).

Utilizing a scanning photoelectron microscope (SPEM) and grazing-incidence X-ray powder diffraction (GIXRD), we studied the electronic band structure and the crystalline properties of the pentanary Cu(In,Ga)(S,Se)2 (CIGSSe) thin-film solar cell as a function of sample depth on measuring the thickness-gradient sample. A novel approach is proposed for studying the depth-dependent information on thin films, which can provide a gradient thickness and a wide cross-section of the sample by polishing process. The results exhibit that the CIGSSe absorber layer possesses four distinct stoichiometries. The growth mechanism of this distinctive compositional distribution formed by a two-stage process is described according to the thermodynamic reaction and the manufacturing process. On the basis of the depth-profiling results, the gradient profiles of the conduction and valence bands were constructed to elucidate the performance of the electrical properties (in this case, Voc = 620 mV, Jsc = 34.6 mA/cm(2), and η = 14.04%); the valence-band maxima (VBM) measured with a SPEM in the spectroscopic mode coincide with this band-structure model, except for a lowering of the VBM observed in the surface region of the absorber layer due to the ordered defect compound (ODC). In addition, the depth-dependent texturing X-ray diffraction pattern presents the crystalline quality and the residual stress for each depth of a thin-film device. We find that the randomly oriented grains in the bottom region of the absorber layer and the different residual stress between the underlying Mo and the absorber interface, which can deteriorate the electrical performance due to peeling-off effect. An anion interstitial defect can be observed on comparing the anion concentration of the elemental distribution with crystalline composition; a few excess sulfur atoms insert in interstitial sites at the front side of the absorber layer, whereas the interstitial selenium atoms insert at the back side.

An insulating-conductive transition of Zn-Sn-O alloy is succeeded in this work driven by the partial crystallization out of the amorphous surrounding. The optimized room temperature mobility of 48 cm(2) V-1 s(-1) and surface roughness of 0.3 nm are achieved in a 125-nm-thick film with a Sn cation composition of 0.44. To our knowledge, the mobility is superior to typical values of transparent conductive oxides under the criterion of a surface roughness less than 1 nm. Moreover, a proper mechanism that an oxygen-deficient amorphous surrounding with a strong ns-orbital overlapping of cations induced by the partial crystallization is the origin of the insulating-conductive transition has been demonstrated through synchrotron radiation experiments. In brief, the mechanism revealed in this work could provide effective information for new potentialities of fabricating transparent electrodes. (C) 2016 Elsevier B.V. All rights reserved.

Two dimensional (2D) vertically-aligned crystalline alpha-Fe2O3 nano-wall arrays were prepared by thermal oxidation of iron substrates under the 03 ambient. It is found that alpha-Fe2O3 nano-partitions can be produced in a process temperature region of 450-500 degrees C. Higher growth temperatures (650-700 degrees C) produced wholly nanowires. The transition from 2D sheet-like nanostructures to 1D nanowires can be described by surface diffusion growth mechanism. The iron oxide nanowires present very weak magnetoresistance at different magnetic fields. However, the alpha-Fe2O3 nano-partitions have very strong magnetoresistive properties which a high of 45% resistance variation obtained at low magnetic field of 300 Gauss. This unique property shows the potential of iron oxide nano-partition arrays in detection magnetic field and solid state memory applications. (C) 2016 Elsevier Ltd. All rights reserved.

The hot-rolled Mg-14.3Li-0.8Zn (HR LZ141) alloy exhibits anisotropic tensile properties with an average value of the normal anisotropic parameter, r(avg), of 0.6. From microstructural observation, it is proposed that the mechanical fibering, which is caused by the preferred alignment of the small alpha-phase particles in the rolling direction, results in this anisotropic property. Both strain rate (epsilon) over dot and temperature T influence the tensile properties. At 6.67 x 10(-5) s(-1) to 6.67 x 10(-2) s(-1) and room temperature, the tensile properties are all linear and sensitive to the log-scale (epsilon) over dot. The strain-rate sensitivity exponent, m, is 0.055 at all testing (epsilon) over dot. The work-hardening exponent, n, is positive, and the higher the (epsilon) over dot is, the larger the n-value is, but the increase in the n-value is quite low for (epsilon) over dot < 3.33 x 10(-4) s(-1) and (epsilon) over dot > 6.67 x 10(-3) s(-1). The yield point phenomenon appears in sigma-epsilon curves at room temperature when (epsilon) over dot = 6.67 x 10(-5) s(-1), and at 343 K when (epsilon) over dot = 3.33 x 10(-3) s(-1). The work-softening phenomenon occurs at T >= 343 K with (epsilon) over dot = 3.33 x 10(-3) s(-1). The yield stress and UTS increase but the elongation decreases as the testing temperature decreases. The Charpy impact test indicates that different notch orientations influence the impact energy due to the formation of mechanical fibering, and the result of impact energy vs. temperature shows no significance of transition temperature.

Self-assembled type-II ZnTe quantum dots (QDs) were grown on GaAs (001) substrates with Zn1−xMgxSe (x=0.24 and 0.52) buffer layers by molecular beam epitaxy. The optical properties of ZnTe QDs were investigated by low-temperature photoluminescence (PL) and time-resolved PL. An abrupt variation of the PL peak energy with coverage implies the existence of wetting layer of 3.2 MLs and 4.0 MLs for the Mg concentration x=0.24 and 0.52, respectively. The thickness of wetting layer is larger than that of ZnTe QDs grown on ZnSe buffer layers because the strain between ZnTe and Zn1−xMgxSe is smaller. The non-mono-exponential decay profiles reflect the processes of carrier transfer and recapture. The Kohlrausch׳s stretching exponential well fits the decay profiles of ZnTe/Zn1−xMgxSe QDs.

In this study, hetero‐epitaxy of GaSe epilayers on a c‐sapphire substrate achieved using molecular beam epitaxy was demonstrated. The GaSe epitaxial growth was monitored using in situ reflection high‐energy electron diffraction (RHEED). Streak RHEED patterns showed a flat and highly crystalline situation. Furthermore, two RHEED patterns were observed after 15 min of growth, and they were correlated with the m‐axis and a‐axis of hexagonal GaSe. The single crystal of GaSe was verified using X‐ray diffraction and high‐resolution cross‐section transmission electron microscopy. The full width at half‐maximum of (0002) in the XRD rocking‐curve spectrum of GaSe epilayer is obtain around 207 arcsec, which is the smallest value observed to date. The epitaxial growth of GaSe demonstrated the feasibility of growing large‐area epilayers.

We show that by using different x-ray irradiation times of BSA-coated Au nanoparticles (NPs) we can change their ultraviolet-stimulated photoluminescence and shift the spectral weight over the visible spectral range. This is due to the interplay of two emission bands, one due to BSA and the other related to gold. The emission properties did not change with time over a period of several months.

The fabrication of gallium, zinc and nickel oxide nanodots for application of resistive random access memory (RRAM) was demonstrated using the atomic force microscopy (AFM) local anodic oxidation technique. Thin metal films were deposited on indium tin oxide conductive glass substrates. In the atmospheric environment, using AFM equipped with an Ag -coated probe can generate metal oxide nanodots locally on the metal films. These nanodots act as an insulator layer in a single unit cell of the RRAM. The voltage-biased method allows devices to reset from a low-resistance state (LRS) to a high-resistance state (HRS) at 0.9 V. These results show the ability of the AFM local anodic oxidation to produce 50 nm NiO nanodots on glass substrates for potentially high-density RRAMs. As we developed the characteristics of the structure, we found that a lateral NiO nanobelt RRAM performs very low power operation from such experimental manufacturing process. Using a current-biased method, the lateral device switches from a HRS to a LRS with a low writing voltage of 0.64 V.

This study discovered the origin of deep level emission in zinc-blende ZnCdSe thin films grown by molecular beam epitaxy, in which a localization behavior was noticed. Pronounced deep level emission observed in films grown under a VI/II ratio of 1.74 (Se-accumulated regime) could be suppressed by a lower VI/II ratio of 1.04 (intermediate regime) and 0.74 (metal-rich regime). Hence the localized states could be correlated to excess selenium accumulated at the growth surface. The localized states also influence the carrier relaxation process of self-assembled ZnTe quantum dots embedded in a ZnCdSe matrix. Once quantum dots surmount the wetting layer, localized electrons in the capping layer dominate the type-II transition and exhibit size-independent lifetimes. (C) 2015 Elsevier B.V. All rights reserved.

The quaternary compound semiconductor (InGaO3(ZnO)m); m=1,2,3…)(IGZO) thin films were fabricated by plasma-assisted molecular beam epitaxy. First, the IGZO thin films were grown under the variation of gallium cell temperature to evaluate the fundamental properties of IGZO. A phase transformation between crystalline and amorphous is observed when the gallium content ratio is higher than 28 at%. It revealed redundancy in the metal, which would self-assist the channel or defect state to destroy the crystal structure. The highest mobility of 74.3cm2/Vs was obtained at 28 at% of gallium. By tuning the element content of quaternary compounds, the ternary plots distribution of IGZO thin films exhibits an amorphous structure in most regions. Therefore, the stoichiometric condition of IGZO, which is 1:1:1:4, is demonstrated at the amorphous structure. Additionally, it transitions to crystalline structure after a 1100°C annealing process.

Cd(Mn, Zn)Te-based ternary compound semiconductors with wide band-gaps are important in the detection of radiation and photovoltaic applications. This study characterizes Cd1-xMnxTe epilayers on Si substrates with various Mn compositions grown by molecular beam epitaxy. The surface smoothness, crystallinity and optical quality all are significantly improved with increasing Mn content. The Cd0.61Mn0.39Te epilayer with a thickness of only about 500 nm yields a full width at half maximum of the X-ray rocking curve of 165 arcsec. Photoluminescence spectra at 10 K show that the intensity of defect-related emissions is much lower than that of binary CdTe epilayers, reaching zero from the samples with high Mn content, while the integral intensity of the exciton-related emissions is increased by more than two orders of magnitude. Raman scattering spectra reveal that the intensity of the Te-Te related defect vibration modes falls significantly as the Mn content increase, even disappearing altogether in the samples with high Mn content. This work proposes that incorporating Mn atoms during epitaxial growth can promote the decomposition of Te-2 sources, owing to the high sticking coefficient of Mn and the high cohesive energy of the Mn-Te bond, and then reduce the number of Te-Te related stacking fault defects, yielding high-quality CdMnTe epilayers. Our results herein demonstrate that the CdMnTe ternary epilayers are much more promising in terms of material quality than the CdZnTe ternary epilayers. (C) 2015 Elsevier B.V. All rights reserved.