Table of Content

15 June 2024, Volume 53 Issue 6

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Reviews

Research Progress on Controlling the Thermal Boundary Resistance of GaN on Diamond

LAN Feifei, LIU Shasha, FANG Shishu, WANG Yingmin, CHENG Hongjuan

2024, 53(6):  913-921. 

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GaN high electron mobility transistor (HEMT) played major roles in radar, 5G communication, aerospace and other fields. With increasingly higher output powers developed, however, heat dissipation has become a severely problem limiting the device performance and deteriorating the device reliability and life span. Diamond has the highest thermal conductivity (＞2 000 W·m^-1·K^-1) of the bulk material. Integration diamond film with GaN HEMT can rapidly extract heat from the junction, which may increase the power density. In this paper, the technical advantages and realization approaches of GaN on diamond are stated, and the effect of the thermal boundary resistance on heat dissipation is discussed. The latest researches on the reducing of the thermal boundary resistance are thoroughly reviewed, the difficulties and development in controlling the thermal boundary resistance are also analyzed. It is clarified that under the condition of limited selection of dielectric layer materials, the thermal boundary resistance can be reduced through the enhancing of the quality of the interface between GaN and diamond.

Research Progress and Prospect of Chalcogenide Perovskite of BaZrS₃ and Its Preparation

DING Tao, LI Qingwen, XU Yuqi, ZHONG Min

2024, 53(6):  922-929. 

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Toxicity and stability of lead halide perovskite are still crucial problem to be solved, and it is necessary to seek non-toxic and stable new optoelectronic materials with similar structure of lead halide perovskites. Chalcogenide perovskite ABX₃(X=S,Se) have become the focus of research recently for its high stability, non-toxicity and being abundant in earth element. ABX₃(X=S,Se) also has good optical and electrical properties, and can be used in various photoelectric materials, making it suitable for various optoelectronic materials. The most widely studied material is chalcogenide perovskite BaZrS₃. BaZrS₃ has suitable direct bandgap, excellent light absorption, good carrier transport properties, excellent chemical stability and environmentally benign nature. This article reviews the latest progress in theoretical calculations, synthesis methods of powders and thin film of BaZrS₃, especially gives in-depth analysis of the synthesis of BaZrS₃. Key issues in the synthesis of BaZrS₃ are discussed. This review will provide important references for new researchers entering this field and promote the further development of safe, stable and environmentally new generation optoelectronic materials.

Research Progress of Indium Oxide-Based Gas Sensitive Materials

LI Yuqi, XU Ying, LIANG Shiming

2024, 53(6):  930-946. 

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This paper systematically reviews the research advancements in indium oxide (In₂O₃)-based gas-sensitive materials and focuses on their potential applications in environmental monitoring and safety. It provides an in-depth analysis of the structure, properties and gas sensing mechanisms of indium oxide, detailing the impact of various synthesis methods (such as hydrothermal and chemical vapor deposition) on the microstructure and performance of the materials. Additionally, this paper discusses the applications of modification techniques, including element doping, material loading and semiconductor compositing in enhancing gas sensitivity. It also analyzes current research challenges and future directions, offering significant perspectives and directions for further research and application of indium oxide-based gas-sensitive materials.

Research Articles

Growth and Properties of Large Size and High Quality Cr³⁺∶BeAl₂O₄ Crystals

WANG Hongyan, WANG Shiwu, NIE Yi, ZHANG Xingyu, ZHANG Fang, XU Hui, LI Ruimao, KUANG Yongfei

2024, 53(6):  947-952. 

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In this study, large size and high quality alexandrite (Cr³⁺∶BeAl₂O₄) crystals were grown by induction heating Czochralski method combined with automatic diameter control technology. The obtained crystal diameter size reaches 70 mm, the cylinder length reaches 140 mm, and its weight exceeds 2 800 g. Irradiated with a cold light source, there are bubbles in the center area of 10~15 mm. No scattered particles are found in the 8 mm×130 mm crystal rod under the irradiation of a 5 mW green laser. The wavefront distortion is 0.3λ@632.8 nm measured by a Zygo laser interferometer. The Cr³⁺ doping concentrations were measured by inductively coupled plasma atomic emission spectrometry. The axial molar concentration gradients are 0.5×10^-4~1.9×10^-4 cm^-1. The absorption spectra of the alexandrine crystals with different Cr³⁺ doping concentrations at room temperature were measured by Perkin Elmer Lambda-950 UV-Vis near-infrared spectrophotometer and the absorption coefficients were calculated. These results provide important basic data for the application of alexandrite crystals.

Uniformity of Piezoelectric Properties of PIN-PMN-PT Ferroelectric Single Crystals Modulated by Polarization Technique

LIANG Min, XIONG Ruibin, CHEN Shuli, WANG Zujian, SU Rongbing, SU Bin, LIU Ying, HE Chao

2024, 53(6):  953-958. 

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Relaxor ferroelectric single crystals have important applications in medical ultrasound transducers, hydroacoustic devices and other fields due to their excellent piezoelectric properties. The relaxor ferroelectric single crystals grown by the Bridgman method inevitably suffers from component segregation, resulting in extremely low utilization. In this work, the variation of piezoelectric coefficient (d₃₃) and dielectric constant (ε₃₃^T/ε₀) of 0.24PIN-0.46PMN-0.30PT ferroelectric single crystals along the growth direction were tested. The results show that d₃₃ and ε₃₃^T/ε₀ are extremely variable along the growth direction, with less than 20 mm of the region maintaining close performance. Polarization modulations were applied in different regions with close ferroelectric-ferroelectric phase transition temperatures through different polarization designing. The d₃₃ and ε₃₃^T/ε₀ of more than 60% region of the crystalline maintain in the range of (1 500±140) pC·N^-1 and 4 900±350, respectively. In order to verify the consistency of the resonance peaks of the crystal after polarization modulation, the resonance spectra of the k₃₃ vibrators in the two end regions were tested. The results show that the electromechanical coupling coefficients are close to each other, and the peak positions of resonance and anti-resonance are also close to each other. Importantly, there don’t exist additional spurious-mode vibrations. These demonstrate the feasibility of employing polarization modulation to regulate the uniformity of the PIN-PMN-PT ferroelectric single crystals along the growth direction. This work provides a reference solution to improve the utilization of PIN-PMN-PT ferroelectric single crystals.

Study on the Growth of Type-Ib Diamond Single Crystal and the Temperature Field Distribution in the Synthesis Cavities

XIAO Hongyu, LI Yong, TIAN Changhai, ZHANG Weixi, WANG Qiang, XIAO Zhengguo, WANG Ying, JIN Hui, BAO Zhigang, ZHOU Zhenxiang

2024, 53(6):  959-966. 

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In this paper, type-Ib diamond single crystals, using two different sizes of synthesis cavities of 15 mm and 30 mm, were synthesized under 5.7 GPa, 1 560~1 600 K, and the temperature field distributions of the two sizes of synthesis cavities were studied using finite element method (FEM). Firstly, the temperature field distributions of two different sizes of synthesis cavities were simulated using finite element method. The average radial temperature gradient and average axial temperature gradient of the 15 mm synthesis cavity are 0.573 and 5.700 K/mm, respectively. The average radial temperature gradient and average axial temperature gradient of the 30 mm cavity are 0.093 and 2.280 K/mm, respectively. The simulation results reveal that the uniformity of the temperature field in the 30 mm synthesis cavity is significantly better than that in the 15 mm synthesis cavity. Secondly, the reproducible growth of high-quality type-Ib diamond large single crystals was achieved using both synthesis cavities mentioned above. The 15 mm synthetic cavity is difficult to achieve the growth of high-quality type-Ib diamond single crystals weighing more than 1.2 ct (1 ct=0.2 g), while the 30 mm synthetic cavity is more suitable for the growth of large-size high-quality type-Ib diamond single crystals. Furthermore, the scanning electron microscopy (SEM) test results show that the surface flatness of high-quality type-Ib diamond single crystals grown using two different sizes of synthesis cavities in this study is good, and the expansion of the synthesis cavity has no significant effect on the crystal quality of Ib diamond single crystal surface. Finally, Raman spectrum test results show that the crystal quality of polycrystalline diamond deteriorates, and other diamond single crystal samples synthesized by two kinds of synthesis cavity in this study have better crystal quality. This research has certain academic reference value for the design of large size synthesis cavity of gem grade diamond single crystal, the growth of large size diamond single crystal, and the perfection of polycrystalline diamond single crystal synthesis technology.

Effect of SiC Wafer Grinding Process on Surface Damage

XIE Guijiu, ZHANG Wenbin, WANG Yan, SONG Zhen, ZHANG Bing

2024, 53(6):  967-972. 

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With the rapid development of silicon carbide (SiC) power devices and chip technology, the demand for grinding process of SiC wafers has become increasingly crucial due to the escalating requirements for physical strength, heat dissipation and size. Therefore, grinding process of SiC wafers has gradually become an important issue in manuscription processing. Due to its low fracture toughness, the SiC wafers are prone to cracking during grinding processes. It’s a big challenge in achieving an efficient and high-quality grinding process for SiC wafers. Based on the process and principle analysis of SiC wafer grinding, the influence of four key parameters in the grinding process, i.e., grinding wheel size, feed rate, grinding wheel speed and chuck table speed on wafer surface edge breakage, were studied in this paper. The process of improving the processability of wafer by annealing is presented, and the surface integrity improving process of wafer is proposed. The study reveals the control method of wafer grinding processing surface quality, offered an efficient process route for reducing surface damage and improving the surface layer quality of chips, and verified the machining effect through experiments. The relevant results have important guiding significance for the wafer grinding process of hard and brittle materials.

Numerical Simulation Investigation of Size Effect on Calcium Fluoride Crystals Grown by Vertical Bridgman Method

SHI Yufeng, WANG Pengfei, MU Honghe, SU Liangbi

2024, 53(6):  973-981. 

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High-quality, large-size CaF₂ crystals are urgently needed for advanced applications such as deep ultraviolet lithography and aerospace cameras. However, growing such crystals is a challenging task in the field of crystal growth. Heat transfer, flow, and phase change processes of 3, 7, and 20 inch (1 inch=2.54 cm) CaF₂ crystals at different growth stages on the vertical Bridgman growth were conducted by numerical simulation. The results show that as the crystal size increases, the melt flow strength and the area of heat dissipation on the crucible wall increase, resulting in problems such as local depression of the melt-crystal interface, increase in the radial temperature difference, reversal of the temperature difference between the crystal edge and center, and decrease in the axial temperature gradient near the melt-crystal interface. Furthermore, this article discusses optimization strategies for growth rate and power of heater in the growth of large-size CaF₂ crystals.

Nanoindentation Constitutive Equation of Sapphire Crystal

LIU Ting, LI Xianhao, GUO Yaojun, KANG Sen, LU Yarong, HE Lijun

2024, 53(6):  982-990. 

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A constitutive equation was established using finite element method (FEM) combined with neural network optimization and dimensionless model to uniformly describe the nanoindentation behavior of different crystal planes of sapphire crystal. The surface micromechanical behavior of four typical crystal planes (C, A, R, M) of the sapphire crystal was studied using nanoindentation method. The comparison between the calculated results of the constitutive equation and the measured results show that: the loading and unloading curves can be expressed by quadratic functions of the indentation depth h; the loading curve is a function of the elastic modulus E, yield stress Y, and work hardening index n of the intrusion surface, while the unloading curve is also related to the unloading position (the maximum depth) h_max in addition to these three factors; for the same crystal plane, the residual depth h_r is proportional to h_max, and the plastic work W_p is proportional to the third power of h_max. The results also indicate that, for super hard and brittle materials such as sapphire crystal, which are difficult to apply conventional mechanical performance testing methods, the combination of the constitutive equation and nanoindentation testing can effectively obtain their basic mechanical property.

Dielectric Properties of Ionic Crystals Based on the Skanavi Model

LUO Hao, CHENG Pengfei, DANG Ziyan, GENG Kejia, KONG Cuncun, QIN Xinrui, SU Yaoheng

2024, 53(6):  991-998. 

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In this paper, the electronic displacement polarizability and ionic displacement polarizability of each ion in NaCl crystals are calculated by Born circular orbit polarization model and diatomic molecular ionic displacement polarization model. Furthermore, the point dipole approximation and the average field approximation of diatomic molecules are adopted, and the effective electric field structure coefficients of NaCl crystals containing different ion numbers are calculated based on the Skanavi model under the action of additional electric fields generated by polarized ions, and the dielectric constants closer to the measured values are obtained. Compared with the theoretical calculation that treats the effective electric field inside the crystal as the applied macroscopic average electric field, the error value is reduced from 11.4% to 4.3%. The results of this work provide a new method to accurately calculate the dielectric properties of ionic crystals by Skanavi model.

First Principles Study on the Structure-Property Relationship of Alkali Metal Molybdates

ZHANG Bo, WANG Yunjie, QI Yajie, DING Jiafu, HE Zhihao, SU Xin

2024, 53(6):  999-1007. 

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The crystal structures, electronic structures, atomic populations, charge density distributions and birefringence of Li₂MoO₄, Na₂MoO₄, K₂MoO₄ and Rb₂MoO₄ were compared by first principles. The results show that the bandgaps of the four crystals are direct band gaps, the differences of the bandgap between them are not large, and they are all around 4.3 eV. As the radius of alkali metal atoms increases, the contribution of their electronic orbitals to the energy bands moves closer to the high-energy side. The distribution of the bonding boule number and electron density suggests that covalent bonds are formed between Mo and O, and the alkali metal atoms form ionic bonds with O. Rb₂MoO₄ has the highest birefringence of 0.022 5 among the four crystals at 1 064 nm. The refractive indices of the four crystals show that the radius is positively correlated with the birefringence. The study in this paper provides some references for the application of molybdate in nonlinear optical crystals.

Dual-Band Circular Polarizer

HUANG Kaiyan, LI Yang, LI Xiangyu, YAO Xiayuan

2024, 53(6):  1008-1015. 

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In this paper, a novel dual-band circular polarization was proposed, which converts the incident linear polarization electromagnetic waves into left-handed and right-handed circularly polarized waves at 22.1~24.2 and 30.1~33.2 GHz, respectively. These two channels precisely cover the two observation channels of (23.8±0.2) and (31.4±0.1) GHz in atmospheric remote sensing. The insertion loss in the remote sensing observation channel is less than 1 dB, and the axial ratio is better than 1.26. It fully meets the detection requirements of the existing atmospheric remote sensing in two observation channels of (23.8±0.2) and (31.4±0.1) GHz. For designing this circular polarizer, the circuit resonance theory was used to construct the passband, and preliminary analysis was conducted through equivalent circuits. It is optimized by the electromagnetic simulation software to complete the design.

Preparation and Luminescence Properties of Sm³⁺ Doped Na₅Y_1-x(MoO₄)_4-y(WO₄)_y Phosphors with High Thermal Stability

HU Zhengkai, YANG Weibin, XIONG Feibing, GUO Yisheng, BAI Xin, LI Mingming

2024, 53(6):  1016-1025. 

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A series of orange-red phosphors, Na₅Y_1-x(MoO₄)_4-y(WO₄)_y∶xSm³⁺(x=0~0.10, y=0~4), were synthesized by high temperature solid state method. The properties of the phosphor samples were studied by means of X-ray diffraction, transmission electron microscope, normal/variable temperature fluorescence emission spectrum, fluorescence excitation spectrum, fluorescence dynamic attenuation curve, CIE chromaticity coordinates and so on. XRD results show that the phase of the synthesized samples is consistent with the standard of Na₅Y(MoO₄)₄, and the phase structure of the materials is unchanged by introducing Sm³⁺ or (WO₄)^2-. Under the excitation of 406 nm, Na₅Y_0.92(MoO₄)₃(WO₄):0.08Sm³⁺ has the highest emission intensity. With increasing doping concentration of Sm³⁺, the concentration quenching phenomenon appears, and the main reason for the concentration quenching is attributed to the electric dipole-electric dipole interaction. The study found that the doping of rare earth ions in the Na₅Y(MoO₄)₄ matrix would cause electronegativity changes and lattice distortion. The introduction of (WO₄)^2- anionic groups into Na₅Y_1-x(MoO₄)₄∶xSm³⁺ can make up for the defects caused by the doping of Sm³⁺ and further improve the luminescence performance of Na₅Y_1-x(MoO₄)₄∶xSm³⁺ phosphors. In the range from 300 K to 440 K, the samples have excellent thermal stability, and the fluorescence intensity is more than 96% higher than that at room temperature. The CIE chromaticity coordinates are located in the orange-red region. These results indicate that the Na₅Y_1-x(MoO₄)_4-y(WO₄)_y∶xSm³⁺ phosphor has potential value in WLED applications.

Synthesis, Crystal Structure and Properties of a Pyrazinyl Bipyridine Nickel Complex

ZHOU Yunlong, SONG Juan, WU Miao, REN Chuanqing, JIN Lingxia

2024, 53(6):  1026-1033. 

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A new nickel complex [Ni(dpyb)₂](NO₃)₂·(H₂O)₃ was synthesized by means of solvent-thermal synthesis using 2,6-bis(2-pyrazinyl)-3,4′-bipyridine (dpyb), which is one of polynitrogen compounds, as the ligand and Ni(NO₃)₃·6H₂O as raw materials. The structure of the complex [Ni(dpyb)₂](NO₃)₂·(H₂O)₃ was characterized by X-ray single crystal diffraction, infrared spectroscopy and Raman spectroscopy. The results of structural analysis show that the complex was a mononuclear structure, and the mononuclear structure is further extended to the binuclear structure through intermolecular hydrogen bonds between the mononuclear units. The Hirshfeld surface analysis of the target complex was carried out using Crystal Explorer 21 software, and the results show that there is strong hydrogen bonding in the structure of [Ni(dpyb)₂](NO₃)₂·(H₂O)₃. The frontline molecular orbitals and energy band gaps of the free ligand and the complex were also calculated by Gaussian 09W and Gauss View 5.0 software using the B3LYP/6-311G (d, p) method, and the results suggest that the complex has high chemical stability. The results of the computational study are in good agreement with the experiments. In addition, fluorescence analysis of the free ligand and complexe were performed, and the results indicate that compared with the free ligand, the fluorescence intensity of the complex is weakened, which is due to the coordination between the ligand and the Ni(Ⅱ) ion.

Preparation of Nano Ag Decorated Sulfur Doped g-C₃N₄ and Its Photocatalytic Antibacterial Performance

QI Jun, LI Jiale, HU Shan, YU Xiaofeng, LIAO Weixing, HUANG Shiwen, XU Xiuquan

2024, 53(6):  1034-1041. 

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Photocatalytic inactivation has been proved to be one of the most promising strategies for controlling pathogenic microorganisms. Herein, a novel Ag nanoparticles (NPs) decorated sulfur doped g-C₃N₄ (Ag/SCN) composite was successfully prepared by combining thermal polymerization and photoreduction methods using urea and thiobarbituric acid as precursors. The as-prepared samples were characterized by XRD, SEM, TEM, XPS and UV-Vis DRS, the inactivation properties and mechanism against E. coli were investigated in depth. The results indicate that Ag NPs are uniformly and tightly decorated on the surface of SCN and the Ag/SCN composites exhibite significantly enhanced visible light response. When the decorating amount of Ag is 6%, the Ag/SCN-6 achieves the optimal photocatalytic antibacterial activity, which could completely inactivate 6.2 lg CFU·mL^-1 of E. coli within 60 min of visible light irradiation. Moreover, active species trapping experiments reveal that the generated superoxide radicals (·O^-₂) following with holes (h⁺) and hydroxyl radical (·OH) dominate the photocatalytic antibacterial process.

Surface Modification of Tetrapod-Like ZnO Whisker by Cuprous Oxide and Its Photocatalytic Properties

LIU Hong, LIU Huarong, FAN Ximei

2024, 53(6):  1042-1050. 

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Cu₂O/T-ZnOw composite catalysts were prepared by a simple liquid-phase reduction method, in which ethylene glycol (EG) as reducing agent and polyvinyl pyrrolidone (PVP) as surfactant. The phase, morphology, band gap, photoluminescence properties, photodegradation, and recyclable performance of samples were studied in detail. The result shows that PVP plays an important role in the morphology of Cu₂O. It makes Cu₂O crystals deposited on the surface of tetrapod-like ZnO whiskers (T-ZnOw) gradually transformed from cubic to sphericity. When Cu₂O crystals deposited on T-ZnOw surface, the band gap (E_g) of semiconductor catalysts were narrowed, and the recombination of photogenerated electron and hole pairs were effectively reduced, which can significantly improve the photocatalytic activity of semiconductor. The degradation efficiency of methyl orange (MO) solution by composite catalysts is increased to more than 90% after 100 min UV irradiation. At the same condition, the cubic-Cu₂O/T-ZnOw composite shows higher photocatalytic activity than spherical-Cu₂O/T-ZnOw. After six recycles of photocatalytic degradation tests, the degradation rate of samples prepared by 0.06 g PVP can still be maintained more than 80%, which shows that the Cu₂O/T-ZnOw composites have good recyclable performance.

Structural Design and Photocatalytic Antimicrobial Properties of NaTaO₃ Based on Density Functional Theory

WANG Tao, ZHANG Yuhao, YIN Hairong

2024, 53(6):  1051-1060. 

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The photocatalyst NaTaO₃, owing to its notable chemical and thermal stability as well as environmental friendliness, emerges as a versatile candidate capable of meeting diverse demands across various fields. Through ion doping, it is feasible to modulate the electronic structure and performance of NaTaO₃. In this study, employing density functional theory (DFT), electronic structure and optical properties of perovskite-type Na_0.75B_0.25TaO₃ (where B=Cr, Mn, Fe, Cu, Zn) were systematically investigated, elucidating the impact of different transition metal dopants on the band structure and electron density of states in NaTaO₃. The investigation reveals that Cr, Mn, Fe, and Zn doping induces metallic properties, while Na_0.75Cu_0.25TaO₃ exhibits semiconductor characteristics, accompanied by a narrowed bandgap of 1.35 eV. The introduction of Cu introduces new energy levels (Cu 3d and Cu 4s) within the bandgap, positioned at its center, resulting in an upward shift of the valence band. Furthermore, the absorption spectra in the Cu-doped system exhibit a redshift, extending the light absorption wavelength up to 800 nm. Subsequently, the photocatalytic antibacterial performance of NaTaO₃ and Na_0.75Cu_0.25TaO₃ was explored, demonstrating a bactericidal efficiency of 99.99% against Staphylococcus aureus (S. aureus) following Cu ion modulation. Finally, an analysis of potential antibacterial mechanisms was undertaken.

Study on the Characteristics of MoO_3-x Nanoslot SERS Substrate Prepared by Hydrothermal Method

SHU Min, LIANG Junhui, CHEN Da, CHEN Zhao, QIN Laishun

2024, 53(6):  1061-1068. 

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Surface-enhanced Raman scattering (SERS) technology, which enables the rapid detection of trace molecules, has gained widespread attention in areas such as pharmaceutical material analysis, identification of hazardous substance residues, and food safety. The response limit of SERS to the detected substances depends on the performance of the substrate and directly affects the final detection effect. In this paper, MoO_3-x nanoslots with oxygen vacancy defects were successfully prepared by a simple hydrothermal method with the aim of increasing the specific surface area of the substrate and its ability of photoinduced charge transfer between the substrate and the detected substances. The electronic structure, optical properties and surface chemical environment of the MoO_3-x nanoslots were analyzed by a combination of X-ray photoelectron spectroscopy (XPS), ultraviolet-visible spectroscopy (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR). Three organic dye molecules, rhodamine 6G (R6G), crystalline violet (CV) and rose red B (RhB), were detected using the MoO_3-x nanoslots as SERS substrates, and the experimental results show that the detection limit of R6G could reach 10^-10 mol/L, and it has better Raman-enhancing activity compared with the same type of semiconductor substrates.

Study on the Process of Preparing ZnO Thick Film by Electrochemical Deposition Method

LI Ganggui, HUANG Danyang, ZHAO Xiaolong, CAI Yahui, HE Yongning

2024, 53(6):  1069-1077. 

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X-rays have high photon energy, which results in a significant penetration depth in ZnO materials. Therefore, in order to detect X-rays effectively, it is necessary to prepare ZnO films with a thickness of micrometers or hundreds of micrometers. In this paper, a 14.85 μm-thick ZnO film was rapidly prepared by electrochemical deposition method. The experimental results show that the deposition potential and electrode material have a significant effect on the deposition rate and surface morphology of ZnO films. With increasing the deposition potential, the morphology of ZnO changes from hexagonal columnar to lamellar structure. When the potential is too high, a large amount of hydrogen is generated, resulting in an increase in the number of holes in the film that prevent it from forming. When using metal Pt as the anode electrode, the solution will gradually acidify, resulting in the dissolution of ZnO as it is deposited, and when the rates of the two coincide, the ZnO film thickness will no longer increase, making it unsuitable for growing ZnO thick films. In contrast, when using metal Zn as the anode electrode, the pH of the solution remains essentially unchanged, which is more suitable for growing ZnO thick films. A ZnO thick film of 14.85 μm was grown for 1 h using metallic Zn as the anode electrode with a deposition potential of 0.65 V and an electrolyte concentration of 0.4 mol/L. When biased at 5 V, the ZnO thick film based detector has been shown to achieve a responsivity of 66.8 μC·Gy^-1·cm^-2 to X-rays with an accelerating voltage of 40 kV.

Study on the Modification of Zinc Anode with LaF₃ Coating in Aqueous Zinc-Ion Batteries

LIU Yuqiu, YANG Juan, LI Xin, LONG Huan, WU Xianwen, WU Xiangsi

2024, 53(6):  1078-1085. 

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The lanthanum fluoride layer functions as an insulator, and its corrosion resistance and low polarization contribute to the facilitation of zinc ion diffusion while suppressing hydrogen evolution, thereby effectively reducing electrode interface impedance. In this paper, a precipitation method was employed to prepare a spin-coated lanthanum fluoride coating on commercial zinc foil in order to investigate its impact on dendritic growth of zinc and electrochemical performance of the full cell. The results demonstrate that the lanthanum fluoride coating significantly reduces both nucleation energy barrier and overpotential for Zn²⁺. Zn@LaF₃ symmetric cells exhibit exceptional cycle life (over 3 000 h) at a current density of 1.0 mA·cm^-1. Even after undergoing 3 000 cycles at high current density, Zn@LaF₃||VO₂ full cells still retain 75.8% capacity (116 mAh/g), which is substantially higher than that observe in Zn||VO₂ full cells (33 mAh/g). Utilizing lanthanum fluoride as a negative electrode coating for zinc provides a practical approach towards constructing dendrite-free zinc negative electrodes and achieving high-performance aqueous zinc-ion batteries.