Bismuth Selenide Research Articles

P–T conditions of metamorphic and hydrothermal events at Tick Hill gold deposit, Mount Isa, Queensland, Australia

Tick Hill gold deposit is a unique gold mineralisation style in the Mary Kathleen Fold Belt in the Mount Isa Inlier. The gold at Tick Hill is generally pure without silver and was formed during two discrete metamorphic-deformation events (D1 and D3). Early gold was observed as inclusions or coarse grains hosted within D1 peak-metamorphic diopside, scapolite and hornblende from the garnet–biotite–hornblende (tschemakite)–plagioclase (andesine)–quartz assemblage. Late gold is closely associated with bismuth selenide, chlorite, albite, sericite and K-feldspar, and formed during D3. The syn-D1 garnet–plagioclase–hornblende–quartz–biotite assemblage was used to constrain the pressure and temperature (P–T) conditions of metamorphism and mineralisation using the garnet–plagioclase–hornblende–quartz barometer and the hornblende–plagioclase, garnet–biotite and garnet–hornblende thermometers. The results show that peak metamorphism at Tick Hill reached P–T conditions of 6.0–7.6 kbar and 720–760 °C. These P–T conditions together with gneissic and migmatisation textures recorded in different rock types at the Tick Hill area indicate that the peak metamorphism preserved in the area occurred at the amphibolite–granulite facies, compared with the amphibolite facies at the southern Mary Kathleen and Eastern Fold Belt. The D3 chlorite, which formed during stage 2 to stage 4 mineralisation events, displays a wide range of compositions reflecting a gradual retrograde temperature change from ∼380 °C to ∼130 °C. The pressures during D3 could not be reliably determined, but the presence of various Bi-selenides suggests that towards the waning stages of D3, the rocks may have been exhumed to a pressure less than 1 kbar.

Enhancing thermoelectric behavior of Bismuth Selenide crystal via substitution of Sulfur and Tellurium

Sulfur and Tellurium substituted Bismuth Selenide (Bi2Se3-x-ySxTey, x = y = 0, 0.1, 0.15, 0.2) quaternary alloy crystals were synthesized by using vertical Bridgman technique. Energy dispersive analysis of X-rays confirmed elemental composition and purity of the grown crystals. Field emission scanning electron microscopy showed that the growth of crystals has occurred by layer growth mechanism. Rhombohedral crystal structure is validated through analysis of powder X-ray diffraction pattern. Thermoelectric parameters such as electrical conductivity, Seebeck coefficient and thermal conductivity were calculated from 303 K to 773 K and from that power factor as well as figure of merit have been determined for all grown crystals. Electrical conductivity significantly increased due to Sulfur and Tellurium incorporation and maximum value obtained is 147.72 S/cm at 503 K for Bi2Se2.6S0.2Te0.2. Seebeck coefficient and thermal conductivity showed decrement with incorporation of Sulfur and Tellurium. Reduction in thermal conductivity and enhancement in electrical conductivity resulted in the improvement of figure of merit. Sulfur and Tellurium substitution showed considerable improvement in ZT from 0.31 (533 K) for pristine Bi2Se3 to 1.28 (523 K) for Bi2Se2.6S0.2Te0.2.

PHASE RELATIONS IN THE Bi2-Bi2Se3-Bi2Te3 SYSTEM AND CHARACTERIZATION OF SOLID SOLUTIONS

Phase relations in the Bi2–Bi2Se3–Bi2Te3 system were determined experimentally using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Based on the experimental results, a solid-phase equilibria diagram at room temperature, a projection of the liquidus surface, and several polythermal sections of the phase diagram were constructed. The regions of primary crystallization and phase homogeneity, types, and coordinates of non- and monovariant equilibria were determined. Continuous solid solutions along the Bi8Se9–Bi8Te9, BiSe–BiTe, and Bi4Se3–Bi4Te3 sections, as well as wide areas of solid solutions based on other bismuth selenides and tellurides, were found. The established phase diagrams can be used for the synthesis of solid solutions of a given composition and the growth of their single crystals by directional crystallization from solution-melts

Ultrafast acousto-optic modulation at the near-infrared spectral range by interlayer vibrations

Abstract The acousto-optic modulation over a broad near-infrared (NIR) spectrum with high speed, excellent integrability, and relatively simple scheme is crucial for the application of next-generation opto-electronic and photonic devices. This study aims to experimentally demonstrate ultrafast acousto-optic phenomena in the broad NIR spectral range of 0.77–1.1 eV (1130–1610 nm). Hundreds of GHz of light modulation are revealed in an all-optical configuration by combining ultrafast optical spectroscopy and light–sound conversion in 10–20 nm-thick bismuth selenide (Bi2Se3) van der Waals thin films. The modified optical transition energy and the line shape in the NIR band indicate phonon–photon interactions, resulting in a modulation of optical characteristics by the photoexcited interlayer vibrations in Bi2Se3. This all-optical, ultrafast acousto-optic modulation approach may open avenues for next-generation nanophotonic applications, including optical communications and processing, due to the synergistic combination of large-area capability, high photo-responsivity, and frequency tunability in the NIR spectral range.

Tailoring Bi2Se3 Topological Insulator for Visible-NIR Photodetectors with Schottky Contacts Using Liquid Phase Exfoliation.

Layered semiconductors of the V-VI group have attracted considerable attention in optoelectronic applications owing to their atomically thin structures. They offer thickness-dependent optical and electronic properties, promising ultrafast response time, and high sensitivity. Compared to the bulk, 2D bismuth selenide (Bi2Se3) is recently considered a highly promising material. In this study, 2D nanosheets are synthesized by prolonged sonication in two different solvents, such as N-methyl-2-pyrrolidone (NMP) and chitosan-acetic acid solution (CS-HAc), using the liquid-phase exfoliation (LPE) method. X-ray diffraction confirms the amorphous nature of exfoliated 2D nanosheets with maximum peak intensity at the same position (015) crystal plane as that obtained in its bulk counterpart. SEM confirms the thin 2D nanosheet-like morphology. Successful exfoliation of Bi2Se3 nanosheets up to five layers is achieved using CS-HAc solvent. The as-synthesized 2D nanosheets in different solvents are employed to fabricate the photodetector. At minimum selected power density, the photodetector fabricated using exfoliated ultrathin 2D nanosheets exhibits the highest range of responsivity, varying from 15 to 2.5 mA/W, and detectivity ranging from 2.83 × 109 to 6.37 × 107. Ultrathin 2D Bi2Se3 nanosheets have fast rise and fall times, ranging from 0.01 to 0.12 and 0.01 to 0.06 s, respectively, at different wavelengths. Ultrathin Bi2Se3 nanosheets have improved photodetection parameters as compared to multilayered nanosheets due to the high surface to volume ratio, reduced recombination and trapping of charge carrier, improved carrier confinement, and faster carrier transport due to the thin layer.

Pulse irradiation synthesis of metal chalcogenides on flexible substrates for enhanced photothermoelectric performance

High synthesis temperatures and specific growth substrates are typically required to obtain crystalline or oriented inorganic functional thin films, posing a significant challenge for their utilization in large-scale, low-cost (opto-)electronic applications on conventional flexible substrates. Here, we explore a pulse irradiation synthesis (PIS) to prepare thermoelectric metal chalcogenide (e.g., Bi2Se3, SnSe2, and Bi2Te3) films on multiple polymeric substrates. The self-propagating combustion process enables PIS to achieve a synthesis temperature as low as 150 °C, with an ultrafast reaction completed within one second. Beyond the photothermoelectric (PTE) property, the thermal coupling between polymeric substrates and bismuth selenide films is also examined to enhance the PTE performance, resulting in a responsivity of 71.9 V/W and a response time of less than 50 ms at 1550 nm, surpassing most of its counterparts. This PIS platform offers a promising route for realizing flexible PTE or thermoelectric devices in an energy-, time-, and cost-efficient manner.

The effect of charged particle irradiation on the transport properties of bismuth chalcogenide topological insulators: a brief review.

Topological insulators (TIs) offer a novel platform for achieving exciting applications, such as low-power electronics, spintronics, and quantum computation. Hence, the spin-momentum locked and topologically nontrivial surface state of TIs is highly coveted by the research and development industry. Particle irradiation in TIs is a fast-growing field of research owing to the industrial scalability of the particle irradiation technique. Unfortunately, real three-dimensional TI materials, such as bismuth selenide, invariably host a significant population of charged native defects, which cause the ideally insulating bulk to behave like a metal, masking the relatively weak signatures of metallic topological surface states. Particle irradiation has emerged as an effective technique for Fermi energy tuning to achieve an insulating bulk in TI along with other popularly practiced methods, such as substitution doping and electrical gating. Irradiation methods have been used for many years to enhance the thermoelectric properties of bismuth chalcogenides, predominantly by increasing carrier density. In contrast, uncovering the surface states in bismuth-based TI requires the suppression of carrier density via particle irradiation. Hence, the literature on the effect of irradiation on bismuth chalcogenides extends widely to both ends of the spectrum (thermoelectric and topological properties). This review attempts to collate the available literature on particle irradiation-driven Fermi energy tuning and the modification of topological surface states in TI. Recent studies on particle irradiation in TI have focused on precise local modifications in the TI system to induce magnetic topological ordering and surface selective topological superconductivity. Promising proposals for TI-integrated circuits have also been put forth. The eclectic range of irradiation-based studies on TI has been reviewed in this manuscript.

Antibacterial activity against Staphylococcus aureus and Salmonella enterica and Density functional studies on Silver doped Bismuth Selenide nanostructures

The current study uses a hydrothermal technique to demonstrate the antibacterial activity of silver- doped bismuth selenium nanoparticles. Because they are more biocompatible, nanoparticles made of metals, polymers, or lipids are better suited as antibiotics. They behave like molecules, breaking through bacterial cell membranes to obstruct the molecular process. According to the studies, the activity against bacteria is caused by the host immune system being triggered, RNA and protein synthesis being inhibited, biofilm development being inhibited, cell membrane disruption occurring, or reactive oxygen species (ROS) being produced. Low toxicity and a well-established medicinal agent characterize bismuth. It had the property of good X-ray contrast agent due it is huge atomic mass (Z=83). The human body need selenium as a necessary component. In the present work, the prepared Ag doped bismuth selenide nanostructures are characterized using XRD, HRSEM with EDAX. The antibacterial property of Ag doped bismuth selenide nanostructures against gram-positive bacteria S. aureus and gram negative Salmonella enterica analysed by disk diffusion method. The optimized structure, structural parameters, Homo-Lomo, molecular electrostatic potential, dipole moments, polarizability and hyperpolarazibilary are analyzed using DFT method.

Bismuth selenide nanosheet layer materials with peroxidase activity for antimicrobial applications

A new type of bismuth selenide nanosheet layer material was synthesized by solvent thermal method, which is harmless to human body and can be used in combination with hydrogen peroxide solution as a new type of modern insecticide. The particle size of the bismuth selenide nanosheet material is about 80 nm, and it has good dispersion in water. In this experiment, the antibacterial ability of the material was investigated using Escherichia coli and Staphylococcus aureus as bacterial models and plant pathogens such as strawberry gray mold and tomato gray mold as fungal models. In addition, the in vivo bioassay indicated that Bi2Se3+H2O2 possessed effective control against Pepper Anthrax Disease. The biocompatibility of this material was also investigated using human umbilical vein endothelial cells (HUVEC) as a model, and the results showed that the bismuth selenide nanosheet material has good antibacterial ability and biocompatibility.

Elevating the performance of nanoporous bismuth selenide incorporated arch-shaped triboelectric nanogenerator by implementing piezo-tribo coupling effect: harvesting biomechanical energy and low scale energy sensing applications

Elevating the performance of nanoporous bismuth selenide incorporated arch-shaped triboelectric nanogenerator by implementing piezo-tribo coupling effect: harvesting biomechanical energy and low scale energy sensing applications

Bi2Se3 interlayer treatments affecting the Y3Fe5O12 (YIG) platinum spin Seebeck effect

In this work, we present a method to enhance the longitudinal spin Seebeck effect at platinum/yttrium iron garnet (Pt/YIG) interfaces. The introduction of a partial interlayer of bismuth selenide (Bi2Se3, 2.5% surface coverage) interfaces significantly increases (by ∼380%–690%) the spin Seebeck coefficient over equivalent Pt/YIG control devices. Optimal devices are prepared by transferring Bi2Se3 nanoribbons, prepared under anaerobic conditions, onto the YIG (111) chips followed by rapid over-coating with Pt. The deposited Pt/Bi2Se3 nanoribbon/YIG assembly is characterized by scanning electron microscope. The expected elemental compositions of Bi2Se3 and YIG are confirmed by energy dispersive x-ray analysis. A spin Seebeck coefficient of 0.34–0.62 μV/K for Pt/Bi2Se3/YIG is attained for our devices, compared to just 0.09 μV/K for Pt/YIG controls at a 12 K thermal gradient and a magnetic field swept from −50 to +50 mT. Superconducting quantum interference device magnetometer studies indicate that the magnetic moment of Pt/Bi2Se3/YIG treated chips is increased by ∼4% vs control Pt/YIG chips (i.e., a significant increase vs the ±0.06% chip mass reproducibility). Increased surface magnetization is also detected in magnetic force microscope studies of Pt/Bi2Se3/YIG, suggesting that the enhancement of spin injection is associated with the presence of Bi2Se3 nanoribbons.

Magnetoresitance vs. electronic structure in Cu doped single crystalline Bi[formula omitted]Se[formula omitted] 3D topological insulator

Bismuth selenide (Bi2Se3) is one of the 3D topological insulators (TI) that can be characterised as materials of a semiconducting volume and a conductive surface. The evolution of the electronic structure of (Bi1−xCux)2Se3 (x = 0, 0.025, 0.05, 0.09 and 0.125) was investigated by angle-resolved photoemission spectroscopy (ARPES), scanning tunnelling microscopy (STM/STS) and Shubnikov-de Haas oscillations (SdH). The results show that doping with Cu does not change the electronic structure, in particular it does not destroy the nontrivial topology of the system. The lack of superconductivity is discussed in view of intercalated CuxBi2Se3 in which superconductivity is observed.

Magnetotransport Signatures of Superconducting Cooper Pairs Carried by Topological Surface States in Bismuth Selenide.

As topological insulators (TIs) are becoming increasingly intriguing, the community is exploring transformative applications that require interfacing TIs with other materials such as ferromagnets or superconductors. Herein, we report on the manifestations of superconducting electrons carried by topological surface states (TSS) in Bi2Se3 films. As key signatures of TSS-carried Cooper pairs, we uncover the hysteresis of magnetoresistance (MR) and the switching behavior of anisotropic magnetoresistance (AMR). For in-plane fields perpendicular to the injected current, AMR shows negative switching (resistance drop) when the contacts become superconducting, which is consistent with a cooperative Zeeman effect enabled by the spin-momentum locking of TSS. The MR and AMR behaviors are robust, occurring reliably in multiple samples, from different sources, and with different defect concentrations. Our findings can guide novel developments in superconductor/TI quantum devices relying on supercurrent detection as well as lead to more refined transport signatures of Majorana zero-modes in the future.

Characterization of Mechanical Oscillations in Bismuth Selenide Nanowires at Low Temperatures.

A single transistor preamplifier circuit was designed to facilitate electrical detection of mechanical oscillations in nanoelectromechanical systems (NEMSs) at low temperatures. The amplifier was integrated in the close vicinity of the nanowire inside the cryostat to minimize cabling load and interference. The function of the circuit was impedance conversion for current flow measurements in NEMSs with a high internal resistance. The circuit was tested to operate at temperatures as low as 5 K and demonstrated the ability to detect oscillations in double-clamped bismuth selenide nanowires upon excitation by a 0.1 MHz-10 MHz AC signal applied to a mechanically separated gate electrode. A strong resonance frequency dependency on temperature was observed. A relatively weak shift in the oscillation amplitude and resonance frequency was measured when a DC bias voltage was applied to the gate electrode at a constant temperature.

Topological insulator as an efficient catalyst for oxidative carbonylation of amines.

Topological materials have received much attention because of their robust topological surface states, which can be potentially applied in electronics and catalysis. Here, we show that the topological insulator bismuth selenide functions as an efficient catalyst for the oxidative carbonylation of amines with carbon monoxide and dioxygen to synthesize urea derivatives. For example, the carbonylation of butylamine can be completed over bismuth selenide nanoparticle catalyst in 4 hours at 20°C with a yield of 99%, whereas most noble metal-based catalysts do not function at such a low temperature. Density functional theory calculations further reveal that the topological surface states facilitate the activation of dioxygen through a triplet-to-singlet spin-conversion reaction, in which active oxygen species are formed with a barrier of 0.4 electron volts for the subsequent reactions with amine and carbon monoxide.

PH-Responsive Upconversion Mesoporous Silica Nanospheres for Combined Multimodal Diagnostic Imaging and Targeted Photodynamic and Photothermal Cancer Therapy.

Photodynamic therapy (PDT) and photothermal therapy (PTT) have gained considerable attention as potential alternatives to conventional cancer treatments. However, these approaches remain limited by low solubility, poor stability, and inefficient targeting of many common photosensitizers (PSs) and photothermal agents (PTAs). To overcome the aforementioned limitations, we engineered biocompatible and biodegradable tumor-targeted upconversion nanospheres with imaging capabilities. The multifunctional nanospheres consist of a sodium yttrium fluoride core doped with lanthanides (ytterbium, erbium, and gadolinium) and the PTA bismuth selenide (NaYF4:Yb/Er/Gd,Bi2Se3) enveloped in a mesoporous silica shell that encapsulates a PS, chlorin e6 (Ce6), within its pores. NaYF4:Yb/Er converts deeply penetrating near-infrared (NIR) light to visible light, which excites Ce6 to generate cytotoxic reactive oxygen species (ROS), while Bi2Se3 efficiently converts absorbed NIR light to heat. Additionally, Gd enables magnetic resonance imaging of the nanospheres. The mesoporous silica shell is coated with DPPC/cholesterol/DSPE-PEG to retain the encapsulated Ce6 and prevent serum protein adsorption and macrophage recognition that hinder tumor targeting. Finally, the coat is conjugated to the acidity-triggered rational membrane (ATRAM) peptide, which promotes specific and efficient internalization into malignant cells in the mildly acidic microenvironment of tumors. The nanospheres facilitated tumor magnetic resonance and thermal and fluorescence imaging and exhibited potent NIR laser light-induced anticancer effects in vitro and in vivo via combined ROS production and localized hyperthermia, with negligible toxicity to healthy tissue, hence markedly extending survival. Our results demonstrate that the ATRAM-functionalized, lipid/PEG-coated upconversion mesoporous silica nanospheres (ALUMSNs) offer multimodal diagnostic imaging and targeted combinatorial cancer therapy.

A Computer Investigation of the Effect of High-Resistance Layer Inhomogeneities on Resistive Switching in a Bismuth Selenide Microcrystal Structure

This paper continues the analysis of the results of experimental studies of resistive switching in a structure based on a bismuth selenide microcrystal (flake). It was demonstrated earlier by simulations that both the presence of several highly resistive states in the examined structure and the peculiarities of transitions to these states can be explained by the specific behavior of numerous conducting channels permeating the surface high-resistance (defective) layer. The sources of the nucleation of these channels are believed to be nanoprotrusions on the clamping control silver electrode embedded in the surface layer. In this study it is shown that volumetric inhomogeneities of the surface layer, i.e., nanoinclusions with higher conductivity, can serve as additional sources of the channels. The simulation confirms that the behavior of the channels forming near such inhomogeneities is similar to that of the channels growing from the metallic nanoprotrusions.

Fabrication and characterization of (PVDF/PEO)/AgBiSe2 polymeric membrane with enhanced visible light photocatalytic performance

AbstractDriven by the visible band gap, silver bismuth selenide (AgBiSe2) was loaded in PVDF/PEO blend to enhance the photodegradation of Maxilon blue dye. AgBiSe2 nanoparticles were successfully synthesized by facile solvothermal approach and then loaded to PVDF/PEO (80/20) by 10, 20, and 30 wt%, by evaporative casting method. The X‐ray results in tandem with the Fourier transform infrared (FTIR) established the successful fabrication of (PVDF/PEO)/x(AgBiSe2) polymer nanocomposites. The X‐ray analysis verified the formation of hexagonal AgBiSe2 of a crystallite size ranging from 14.3 to 23.24 nm. The FT‐IR results manifested an overlap between functional groups that corroborated the interaction between PVDF and PEO. Peaks of the AgSe, and SeO modes confirmed that the nanofiller and PVDF/PEO blend were successfully incorporated. The micrograph images by field emission scanning electron microscope (FESEM) unraveled the high tendency of AgBiSe2 to form a uniform cluster. The optical band gap was found to be a direct band gap of 2.86 eV for 30 wt% AgBiSe2 proving its validity as visible‐light‐driven photocatalysts. The removal percentages of the prepared membrane are 4.1, 59, 82, and 98 for 0, 10%, 20%, and 30% AgBiSe2 after 300 min of irradiation under simulated sunlight at pH 6.

Optimization of the thickness dependent third order optical nonlinearities of 2D Bi2Se3 layers

The thickness-dependent saturable absorption behaviour of atomically thin bismuth selenide films has been optimized using 515 nm and 1030 nm laser excitation wavelengths. The studies have been performed by the Z-scan technique employing 400 fs laser pulses emitted by a fiber laser at a repetition rate of 100 Hz. The obtained results allowed the determination of the nonlinear optical parameters as a function of the film thickness. Additional studies have been carried out in order to determine the third-order optical nonlinearities as a function of the annealing temperature. The samples have also been studied by spectrophotometry, electron microscopy and X-ray diffraction, which allowed a deeper knowledge of the optical properties, as well as the crystalline structure of the Bi2Se3 material.

Designing bismuth selenide/metal/bismuth selenide thin films to realize the integration of mid- to far-infrared transparency and conductivity

Designing semiconductor/metal/semiconductor (SMS) sandwich structure film is an effective way to combine transparency and conductivity. However, traditional SMS mainly uses metal oxides such as ITO as the semiconductor material, which can only achieve transparency and conductivity in the visible to near-infrared band, but not in the mid-to far-infrared (MFIR) band. Here, we use bismuth selenide as semiconductor material and Ti as metal to construct SMS and achieve excellent MFIR transparent conductive properties. The results show that the conductivity of the SMS is increased by 3.8 times compared with the bismuth selenide, with only 3% decrease in the transmittance in 8–12 μm. Therefore, this study proposes a new material design strategy to solve the bottleneck problem of integrating MFIR transparency and conductivity.