Sb Thin Films Research Articles

Localized anisotropic stress in the sodiation of antimony anode

Although electrode degradation and failure in secondary batteries are hypothesized to stem from the localized chemo-electro-mechanical stress buildup during the charge-discharge process, the exact mechanism of stress generation is poorly understood. We quantitively resolve the stress accumulation in the Sb thin film anode during its gradual phase transitions in the sodiation/desodiation process by combining real-time electro-mechanical and electrochemical measurements with structural information further confirmed by spectroscopic methodologies. In the Sb thin films with (012) planes nearly normal to the surface, ~63% of the total interfacial stress (43.1 N m−1) is accumulated within the first 1/6 of the sodiation process of Na0.5Sb formation with Na-ions inserted between (012) planes. Only a small stress of 4.3 N m−1 is observed in the second 1/6 of the sodiation process due to preferential amorphization and solid solution formation. The last 2/3 of the sodiation process, where NaSb is converted into Na3Sb, generates only 1/3 of total stress (21.2 N m−1) because of the limited in-plane expansion. We also demonstrate that creating buffering voids can greatly reduce stress accumulation, especially during the early stage of the sodiation. The chemo-electro-mechanical insights from this work could serve as quantitative guidelines for the design and optimization of long-lasting Sb anode.

Antimony as a Programmable Element in Integrated Nanophotonics.

The use of nonlinear elements with memory as photonic computing components has seen a huge surge in interest in recent years with the rise of artificial intelligence and machine learning. A key component is the nonlinear element itself. A class of materials known as phase change materials has been extensively used to demonstrate the viability of such computing. However, such materials continue to have relatively slow switching speeds, and issues with cyclability related to phase segregation of phase change alloys. Here, using antimony (Sb) thin films with thicknesses less than 5 nm we demonstrate reversible, ultrafast switching on an integrated photonic platform with retention time of tens of seconds. We use subpicosecond pulses, the shortest used to switch such elements, to program seven distinct memory levels. This portends their use in ultrafast nanophotonic applications ranging from nanophotonic beam steerers to nanoscale integrated elements for photonic computing.

Thickness-Dependent Crystallization of Ultrathin Antimony Thin Films for Monatomic Multilevel Reflectance and Phase Change Memory Designs.

Phase change materials, with more than one reflectance and resistance states, have been a subject of interest in the fields of phase change memories and nanophotonics. Although most current research focuses on rather complex phase change alloys, e.g., Ge2Sb2Te5, recently, monatomic antimony thin films have aroused a lot of interest. One prominent attractive feature is its simplicity, giving fewer reliability issues like segregation and phase separation. However, phase transformation and crystallization properties of ultrathin Sb thin films must be understood to fully incorporate them into future memory and nanophotonics devices. Here, we studied the thickness-dependent crystallization behavior of pulsed laser-deposited ultrathin Sb thin films by employing dynamic ellipsometry. We show that the crystallization temperature and phase transformation speed of as-deposited amorphous Sb thin films are thickness-dependent and can be precisely tuned by controlling the film thickness. Thus, crystallization temperature tuning by thickness can be applied to future memory and nanophotonic devices. As a proof of principle, we designed a heterostructure device with three Sb layers of varying thicknesses with distinct crystallization temperatures. Measurements and simulation results show that it is possible to address these layers individually and produce distinct and multiple reflectance profiles in a single device. In addition, we show that the immiscible nature of Sb and GaSb could open up possible heterostructure device designs with high stability after melt-quench and increased crystallization temperature. Our results demonstrate that the thickness-dependent phase transformation and crystallization dynamics of ultrathin Sb thin films have attractive features for future memory and nanophotonic devices.

Flexible elemental thermoelectrics with ultra-high power density

Flexible thermoelectrics have attracted great attention due to their potential to convert waste heat to electricity to power wearable devices and IoT (Internet of things) sensors. Though organic thin-film thermoelectric materials are popular choice for preparing flexible thermoelectrics, they suffer from low thermoelectric performances due to the low figure of merit zT. In this work, we demonstrate a new strategy to design high-performance thermoelectrics by highlighting the influence of power factors instead of zT. To verify our claim, thermoelectric is prepared through sputtering high-power factor but low zT elemental thin films of Sb (p-type) and Ni (n-type) on a polyimide substrate. In this system, ascribed by the high-power factor (up to 7 mW/mK2), a high power density of up to 4.7 mW/cm2 at a temperature gradient of 50 K can be achieved, even with the low zT (<0.1). In addition, finite element method (FEM) analysis shows that the benefit of high-power factor increases with decreasing film thicknesses. Our results show that in the case of organics and inorganics thin films, maximizing power factor is more important than maximizing zT. This finding serves to guide the design paradigm of thermoelectrics for wearable devices and is useful for the broad organic electronics community.

Sb incorporated SnO2 nanostructured thin films for CO2 gas sensing and humidity sensing applications

Antimony-doped SnO2 (SnO2:Sb) thin films were deposited on glass substrates via sol-gel spin coating and tested for CO2 gas and humidity sensors. The dominant peak (110) of XRD pattern of SnO2:Sb thin films confirmed the cassiterite tetragonal structure regardless of Sb dopant concentration. The spherical particles like morphology were found for all sample and confirmed by scanning electron microscopy (SEM). The transmittance spectra were recorded in the wavelength range 300–800 nm and the optical bandgap was varied from 3.65 to 4.03 eV on increasing Sb concertation in SnO2. From I-V characteristics, sample C3 has the minimum resistivity (1.08 × 108 Ω.cm) and maximum conductivity 9.23 × 10−9 (Ω.cm)−1 at bias voltage 5 V. The gas sensing characteristics of Sb-SnO2 thin films were examined at different operating temperatures (30 °C to 80 °C) for sample C0 to C4. The optimized sample C0 have gas sensor response 78.5% at ambient temperature (30 °C). The higher doping of Sb in SnO2 as sample C3 and C4 were suitable for higher operating temperatures (80 °C) and responses were 18.74% and 71%, respectively. The characteristics of humidity sensors were analysed in relative humidity (%RH) range from 10% to 90%RH for Sb-SnO2 thin films and found suitable for sample C0 at ambient temperature in mid humidity range (35–60%RH). The present study is an attempt to design a cost-effective and low-temperature-based resistive CO2 gas sensor and humidity sensor for the enhancement in sensing properties.

Synthesis and optical properties of Sb-doped ZnO thin film by sol-gel spin coating method

Sb-doped ZnO thin films had been successfully synthesized by the sol-gel spin coating method. The results of XRD analysis of ZnO and Sb-ZnO thin films showed a hexagonal wurtize crystal structure with crystal sizes of 21,251 nm and 11.265 nm, respectively. The results of SEM analysis showed that the grain size distribution of the crystallites was round and uniform, compactly covering the substrate and almost no porosity. The percentage of Sb concentration based on EDS analysis was 3.02%. UV-Vis analysis results showed the absorbance and transmittance values of Sb-ZnO thin films were higher than the transmittance values of ZnO thin films. The energy band gaps for ZnO and ZnO:Sb thin films were 3.20 eV and 3.30 eV, respectively.

Электронная микроскопия микроструктуры тонких пленок сурьмы переменной толщины

Thin Sb films with a thickness gradient deposited in vacuum were investigated by transmission electron microscopy. Microstructures in films with increasing thickness change from amorphous islands of increasing density and size to labyrinthine and continuous films with texturing, which also changes with increasing thickness. Based on the analysis of the patterns of bend extinction contours, a strong internal bending of the crystal lattice, up to 120 deg/μm, and the dependence of the crystallographic orientations in the structures of the film on the thickness were revealed.

Electron microscopy of the microstructure of antimony thin films of variable thickness

Thin Sb films with a thickness gradient deposited in vacuum were investigated by transmission electron microscopy. Microstructures in films with increasing thickness change from amorphous islands of increasing density and size to labyrinthine and continuous films with texturing, which also changes with increasing thickness. Based on the analysis of the patterns of bend extinction contours, a strong internal bending of the crystal lattice, up to 120 deg/μm, and the dependence of the crystallographic orientations in the structures of the film on the thickness were revealed. Keywords: Antimony, thin films, TEM, crystallography, extinction bend contours.

The structural, optical and morphological study of pulsed laser fabricated Sb doped tin oxide film

Antimony (Sb) doped tin oxide (SnO2) thin film (ATO) is considered as a salient transparent conducting material for optoelectronic and sensor applications due to its low electrical resistivity. In this study, SnO2:Sb thin film have been fabricated on glass substrates by ablating Sb doped SnO2 target using Nd-YAG laser operating at 1064 nm. The films were fabricated at optimized substrate temperature of 450 and 20 Pa partial O2 pressure. The structural, morphological and optical characteristics of the films were studied. SEM micrographs revealed a hexagonal flake like surface of these doped films. The optical energy band gap is increased from 3.21 eV for pure SnO2 to 3.51 eV when doped with 2 wt% Sb. The optical transmittance of 2 wt% Sb doped SnO2 film is nearly 72 % and which was the best for the optimized doping concentration.

Improved Thermal Stability of Monatomic Sb Thin Films Alloyed with Sb &lt;sub&gt;2&lt;/sub&gt;S &lt;sub&gt;3&lt;/sub&gt; by Spontaneous Self-Decomposition

Improved Thermal Stability of Monatomic Sb Thin Films Alloyed with Sb &lt;sub&gt;2&lt;/sub&gt;S &lt;sub&gt;3&lt;/sub&gt; by Spontaneous Self-Decomposition

Improved Thermal Stability of Monatomic Sb Thin Films Alloyed with Sb2s3 by Spontaneous Self-Decomposition

Improved Thermal Stability of Monatomic Sb Thin Films Alloyed with Sb2s3 by Spontaneous Self-Decomposition

Self-powered and broadband flexible photodetectors based on vapor deposition grown antimony film

Antimony (Sb) thin film has drawn substantial attention in recent years due to its high carrier mobility, tunable bandgap, superior thermal conductivity, and high stability. Here, two kinds of Sb photodetector are presented. The Sb photodetector based on SiO2/Si exhibits fast photoresponse from ultraviolet (UV) to near infrared (NIR) wavelengths and a self-powered behavior without bias voltage. The Sb photodetector based on flexible polyimide (PI) substrate also exhibits self-powered and fast photoresponse features similar to the rigid Sb/SiO2 photodetector, furthermore the flexible photodetector exhibits excellent mechanical flexibility and stable photoresponse under a wide bending range of curvatures and a large number of bending cycles. The results of this work indicate that Sb thin film has a great potential in the development of self-powered, flexible, and broadband photodetector in the future.

Performance Improvement of Sb Phase Change Thin Film by Y Doping

Yttrium-doped Sb phase change thin films were prepared by magnetron sputtering and the in-situ resistance temperature measurement system was used to study the process of phase change thin films. With the addition of yttrium atoms, the crystallization temperature of Sb thin film increases, indicating improvement of their thermal stability and data retention ability. Furthermore, yttrium-doped Sb thin films have higher crystalline and amorphous resistance, which is conducive to the phase transition by Joule heating under electric pulse current. The optical band gap energy increases after yttrium doping, which means lower conductivity and higher conduction activation energy. X-ray diffraction shows that the doping of yttrium atoms can inhibit the grain growth and refine the grain size. X-ray photoelectron spectroscopy was used to examine the chemical state of the element, indicating the formation of a new Y-Sb bond, which verifies the improvement of stability. According to atomic force microscopy images, the yttrium-doped Sb material exhibits a surface morphology with less roughness, implying better interfacial properties and reliability. In general, yttrium-doped Sb thin films have better development in the application of phase change memory.

Thickness effect on the crystallization characteristic of RF sputtered Sb thin films

Thickness effect on the crystallization characteristic of RF sputtered Sb thin films

Crystallization mechanism and switching behavior of In–S–Sb phase change thin films

The crystallization mechanism of In2S3-doped Sb thin films is studied in detail to verify the potential application in phase change memory. Here, we observe directly that two different crystallization behaviors can exist in In–S–Sb thin layers by using aberration-corrected scanning transmission electron microscopy. The difference between Sb53.3(In2S3)46.7 and Sb30.9(In2S3)69.1 materials is induced by phase separation. The crystallization mechanism of the Sb53.3(In2S3)46.7 material is related to the formation of the nanocomposite structure with continuous precipitation of Sb nanocrystals. The crystallization characteristic of the Sb30.9(In2S3)69.1 material originates from the diffusion-driven In–S/In–S–Sb interface formation that acts as a “n–p” heterojunction, thereby resulting in the “depletion layer effect” and decreasing the carrier density to 7.42 × 1020 cm−3 at 280 °C. Sb30.9(In2S3)69.1 shows good bipolar-type resistance switching characteristics as the conventional Ge2Sb2Te5. This work provides clear experimental evidence to deepen the understanding of the crystallization mechanism for indium chalcogenides alloyed with Sb films, contributing to the improved control of the phase change behavior to establish high-performance multi-level nonvolatile memory and neuromorphic synaptic systems.

Synthesis of ZnO: Sb thin films Dropped on glass and Porous Silicon for CO Gas Sensing

Membranes Structural properties have been studied using XRD and compare the different values of the average crystallite size by using correction equations. undoped ZnO and ZnO: Sb for (0.5- 2) % membranes has been dropped on glass and p-type porous silicon (PS) substrate at 400 °C to use it as a sensor for CO gas. The crystal growth of the films that were deposited on the PS was not uniform due to the nature of the PS surface and due to the breakage of the crystal structure of the membrane material. the sensitivity of membranes dropped on (PS) for CO gas was higher than on glass substrate.

Properties of In2O3:Sb Thin Films Deposited on Quartz Substrates by Radio-Frequency Magnetron Sputtering

Antimony-doped indium oxide thin films were deposited on quartz substrates by radio-frequency (RF) magnetron sputtering at various growth temperatures in the range of 25–400 °C. The effects of growth temperature on the structural, morphological, optical, and electrical properties of the In2O3:Sb thin films were investigated using X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectrophotometry, and a Hall effect measurement system. The thin films showed a cubic structure with a dominant (222) diffraction peak, and a large number of spherical particles with an average size of approximately 100 nm and a thickness of 190 nm were evolved at a growth temperature of 400 °C. Growing the thin film at higher growth temperatures resulted in an increase in the figure of merit, grain size, and electron concentration, and a decrease in the optical band gap, electrical resistivity, and average transmittance in the wavelength range of 450–1100 nm. The results suggest that the optimal growth temperature for fabricating high-quality RF-sputtered In2O3:Sb thin films is 400 °C.

Optical manipulation of nebulizer spray pyrolysed ZnS thin films for photodetector applications: Effect of Al, Sn and Sb doping

Abstract In this work, we report the structural, morphological, optical and photo-sensing properties of pure as well as Al, Sn and Sb-doped ZnS thin films, with the prospect of photo-sensing and photo-detection applications. ZnS, ZnS:Al(1%), ZnS:Sn(1%) and ZnS:Sb(1%) thin films are fabricated by the spray pyrolysis method. These thin films exhibit polycrystalline nature and crystallize in hexagonal wurtzite ZnS structure. Optical properties reveal the semiconductor behavior of all the films. The optical bandgap (Eg) values, which are around 3.67 eV, 3.43 eV, 3.32 eV and 3.56 eV for ZnS, ZnS:Al(1%), ZnS:Sn(1%) and ZnS:Sb(1%) thin films, respectively, decrease with Al, Sn and Sb-doping. On the other hand, doping of Al, Sn and Sb into the ZnS lattice enhances the photo-sensing parameters such as responsivity (R) and external quantum efficiency (EQE). Al-doping into the ZnS does not affect detectivity (D*) but Sb-doping results in a decrement of D*-value. ZnS:Sn(1%) photo-detector exhibits the highest R, EQE and D*-values of 1.05 × 10−1 AW−1, 33.9% and 4.29 × 1010 Jones, respectively, among all the fabricated photo-devices. Thus doping of post-transition (Al, Sn) and metalloid (Sb) elements into the ZnS host lattice significantly alter the optical and photo-sensing properties of the present thin films.

Preparation and modification of ZnSb-based phase change storage films

In this study, the mechanical and electrical properties of Zn–Sb thin films with different Zn contents were focused; the corresponding improvement mechanism is also discussed. It is found that the maximum phase transition temperature of the film is 250 °C when the Zn content is about 50 at%. The crystallization activation energy of the film also reached a maximum of 4.549 eV. The micro-structure analysis result of these annealed films through XRD showed that when the Zn content is less than 50 at.%, the Sb crystallization firstly reduces the amorphous thermal stability of the material, while the film with the highest crystallization activation energy forms the ZnSb phase. Besides, adding N element greatly increases the resistance ratio of the film before and after the phase change and the phase change temperature point, the maximum temperature reaches 265 °C, and the resistance ratio reaches 104 orders of magnitude. The doping of N also increases the density of the deposited film. When the N content is less, some N elements fill the defects caused by physical deposition, increase the density of the film, and increase the phase transition temperature of the film. The N atoms in the film are more likely to bond with Zn when N content is high, forming a Zn–N bond, and even forming a Zn3N2 phase, so that the phase transition temperature of the film is lowered.

Evolution of Fe 3d impurity band state as the origin of high Curie temperature in the p -type ferromagnetic semiconductor (Ga,Fe)Sb

(Ga$_{1-x}$,Fe$_x$)Sb is one of the promising ferromagnetic semiconductors for spintronic device applications because its Curie temperature ($T_{\rm C}$) is above 300 K when the Fe concentration $x$ is equal to or higher than ~0.20. However, the origin of the high $T_{\rm C}$ in (Ga,Fe)Sb remains to be elucidated. To address this issue, we use resonant photoemission spectroscopy (RPES) and first-principles calculations to investigate the $x$ dependence of the Fe 3$d$ states in (Ga$_{1-x}$,Fe$_x$)Sb ($x$ = 0.05, 0.15, and 0.25) thin films. The observed Fe 2$p$-3$d$ RPES spectra reveal that the Fe-3$d$ impurity band (IB) crossing the Fermi level becomes broader with increasing $x$, which is qualitatively consistent with the picture of double-exchange interaction. Comparison between the obtained Fe-3$d$ partial density of states and the first-principles calculations suggests that the Fe-3$d$ IB originates from the minority-spin ($\downarrow$) $e$ states. The results indicate that enhancement of the interaction between $e_\downarrow$ electrons with increasing $x$ is the origin of the high $T_{\rm C}$ in (Ga,Fe)Sb.