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16 pages, 5535 KiB

Open AccessArticle

Decision Tree-Supported Analysis of Gallium Arsenide Growth Using the LEC Method

by Xia Tang, Gagan Kumar Chappa, Lucas Vieira, Martin Holena and Natasha Dropka

Crystals 2023, 13(12), 1659; https://doi.org/10.3390/cryst13121659 - 2 Dec 2023

Cited by 1 | Viewed by 1338

Abstract

In this study, an axisymmetric Czochralski furnace model for the LEC growth of gallium arsenide is presented. We produced 88 datasets through computational fluid dynamics simulations. Among the many parameters that affect crystal growth, a total of 13 input parameters were selected, including [...] Read more.

In this study, an axisymmetric Czochralski furnace model for the LEC growth of gallium arsenide is presented. We produced 88 datasets through computational fluid dynamics simulations. Among the many parameters that affect crystal growth, a total of 13 input parameters were selected, including the geometry and material parameters of the hot zone (crucible, heaters, radiation shield, and crystal), as well as the process parameters (such as pulling and rotation rates, heating power, etc.). Voronkov criteria (v/G_n), interface deflection, and the average interface temperature gradient were selected as the output parameters. We carried out a correlation analysis between the variables and used decision trees to study the impact of the 13 input variables on the output variables. The results indicated that in the growth of gallium arsenide, the main factor affecting interface deflection and the average interface thermal gradients is the crucible rotation rate. For v/G_n, it is the pulling rate. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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13 pages, 3541 KiB

Open AccessArticle

Type-II GaSe/MoS₂ van der Waals Heterojunction for High-Performance Flexible Photodetector

by Shuai Wang, Xiaoqiu Tang, Ezimetjan Alim, Xingdong Sun, Zheng Wei, Hualong Tao, Yang Wen, Sumei Wu, Yongqing Cai, Yingying Wang, Yao Liang and Zhihua Zhang

Crystals 2023, 13(11), 1602; https://doi.org/10.3390/cryst13111602 - 20 Nov 2023

Cited by 2 | Viewed by 1633

Abstract

In recent years, two-dimensional (2D) type-II van der Waals (vdW) heterojunctions have emerged as promising candidates for high-performance photodetectors. However, direct experimental evidence confirming the enhancement of photoelectric properties by the heterojunction’s type and structure remains scarce. In this work, we present flexible [...] Read more.

In recent years, two-dimensional (2D) type-II van der Waals (vdW) heterojunctions have emerged as promising candidates for high-performance photodetectors. However, direct experimental evidence confirming the enhancement of photoelectric properties by the heterojunction’s type and structure remains scarce. In this work, we present flexible photodetectors based on individual GaSe and MoS₂, as well as a vertically stacked type-II GaSe/MoS₂ vdW heterojunction on polyethylene terephthalate (PET) substrate. These devices demonstrate outstanding responsivities and rapid response speeds, ensuring stable and repeatable light detection. It is notable that the GaSe/MoS₂ heterojunction photodetector exhibits the highest on-off ratio and fastest response speed, attributed to the formation of type-II band alignment. Furthermore, the GaSe/MoS₂ heterojunction photodetector maintains robust stability even in a bent state, highlighting remarkable flexibility. This work exemplifies the type-II vdW heterojunctions in enhancing photoelectric properties through direct in-situ experimentation, laying the groundwork for practical applications of 2D flexible photodetectors. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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10 pages, 2296 KiB

Open AccessArticle

Polypyrrole Film Decorated Manganese Oxide Electrode Materials for High-Efficient Aqueous Zinc Ion Battery

by Yi Liu, Yuyin Zhang and Xiang Wu

Crystals 2023, 13(10), 1445; https://doi.org/10.3390/cryst13101445 - 28 Sep 2023

Cited by 3 | Viewed by 1023

Abstract

Aqueous zinc-ion batteries (AZIBs) have raised wide concern as a new generation energy storage device due to their high capacity, low cost, and environmental friendliness. It is a crucial step to develop the ideal cathode materials that match well with the Zn anode. [...] Read more.

Aqueous zinc-ion batteries (AZIBs) have raised wide concern as a new generation energy storage device due to their high capacity, low cost, and environmental friendliness. It is a crucial step to develop the ideal cathode materials that match well with the Zn anode. In this work, we report polypyrrole-(PPy)-encapsulated MnO₂ nanowires as cathode materials for AZIBs. The assembled Zn//MnO₂@PPy batteries deliver a reversible capacity of 385.7 mAh g⁻¹ at a current density of 0.1 A g⁻¹. Also, they possess an energy density of 192 Wh kg⁻¹ at a power density of 50 W kg⁻¹. The cells show long-term cycling stability, with a retention rate of 96% after 1000 cycles. The outstanding electrochemical performance indicates their potential applications in large-scale energy storage. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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16 pages, 20620 KiB

Open AccessFeature PaperArticle

Controllable Synthesis of Nano-Micro Calcium Carbonate Mediated by Additive Engineering

by Yuke Shen, Shuang Hao, Angqian Suonan, Yanxia Liu, Hangqi Li, Wei Ma, Lin Zhao and Yagang Zhang

Crystals 2023, 13(10), 1432; https://doi.org/10.3390/cryst13101432 - 27 Sep 2023

Cited by 4 | Viewed by 2738

Abstract

Nano-micro calcium carbonate has a small particle size, uniform distribution, and good dispersion performance, offering great research value and development prospects. It has been widely used as a filler material for rubber, paper, ink, pigments, and coatings. Developing an efficient and controllable approach [...] Read more.

Nano-micro calcium carbonate has a small particle size, uniform distribution, and good dispersion performance, offering great research value and development prospects. It has been widely used as a filler material for rubber, paper, ink, pigments, and coatings. Developing an efficient and controllable approach to preparing nano-micro calcium carbonate with adjustable morphology and controllable size has significant economic and environmental benefits. This study reports the controllable synthesis of nano-micro calcium carbonate meditated by additive engineering. The effects of various additives including inorganic acids, organic acids, alcohol, and surfactants on the particle size and morphology of the prepared materials were investigated. SEM, FT-IR and other characterization methods were used to analyze the prepared nano-micro calcium carbonate particle size, dispersion, and uniformity. The results showed that the particle size of calcium carbonate was 4~7 μm with a cubic structure. The particle size of calcium carbonate prepared by adding surfactant additives is in the range of 1~4 μm, and the crystal shape of calcium carbonate changes from calcite to vaterite after adding sodium dodecyl benzene sulfonate. With the aid of additives, the calcium carbonate particles dispersed more evenly. The mechanism of the controllable synthesis of nano-micro calcium carbonate mediated by additive engineering is elucidated and discussed. SDBS was found to be the best additive for preparing nano-micro calcium carbonate, and the synthesis conditions were explored and optimized. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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13 pages, 5675 KiB

Open AccessArticle

Simple Synthesis of 3D Ground-Moss-Shaped MnO@N-C Composite as Superior Anode Material for Lithium-Ion Batteries

by Yanjun Zhai, Longhui Gai, Yingjian Gao, Ziwei Tong, Wenlin Wang, Huimei Cao, Suyuan Zeng, Konggang Qu, Zhongchao Bai, Gang Tian and Nana Wang

Crystals 2023, 13(10), 1420; https://doi.org/10.3390/cryst13101420 - 24 Sep 2023

Viewed by 1173

Abstract

A MnO@N-doped carbon (MnO@N-C) composite, with a three-dimensional (3D) ground-moss-like structure, was synthesized through hydrothermal treatment, polydopamine coating, and calcination, all without the use of surfactants. In lithium-ion batteries, the MnO@N-C sample, when used as an anode, achieved a performance of 563 mAh [...] Read more.

A MnO@N-doped carbon (MnO@N-C) composite, with a three-dimensional (3D) ground-moss-like structure, was synthesized through hydrothermal treatment, polydopamine coating, and calcination, all without the use of surfactants. In lithium-ion batteries, the MnO@N-C sample, when used as an anode, achieved a performance of 563 mAh g⁻¹ at 1.0 A g⁻¹ across 300 cycles and boasted an initial Coulombic efficiency of 73.2%. In contrast, the MnO electrode had a discharge capacity of 258 mAh g⁻¹ and an efficiency of 53.3% under the same conditions. The improved performance stems from the 3D carbon networks hosting MnO. These networks enhance MnO’s electron transfer ability and offer space to offset volume changes during the charge–discharge cycle. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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9 pages, 1785 KiB

Open AccessArticle

Batch Production of Wafer-Scale Monolayer MoS₂

by Zheng Wei, Xingdong Sun, Yongqing Cai, Yao Liang and Zhihua Zhang

Crystals 2023, 13(8), 1275; https://doi.org/10.3390/cryst13081275 - 18 Aug 2023

Cited by 1 | Viewed by 1810

Abstract

Monolayer MoS₂ has emerged as a highly promising candidate for next-generation electronics. However, the production of monolayer MoS₂ with a high yield and low cost remains a challenge that impedes its practical application. Here, a significant breakthrough in the batch production [...] Read more.

Monolayer MoS₂ has emerged as a highly promising candidate for next-generation electronics. However, the production of monolayer MoS₂ with a high yield and low cost remains a challenge that impedes its practical application. Here, a significant breakthrough in the batch production of wafer-scale monolayer MoS₂ via chemical vapor deposition is reported. Notably, a single preparation process enables the growth of multiple wafers simultaneously. The homogeneity and cleanliness of the entire wafer, as well as the consistency of different wafers within a batch, are demonstrated via morphology characterizations and spectroscopic measurements. Field-effect transistors fabricated using the grown MoS₂ exhibit excellent electrical performances, confirming the high quality of the films obtained via this novel batch production method. Additionally, we successfully demonstrate the batch production of wafer-scale oxygen-doped MoS₂ films via in situ oxygen doping. This work establishes a pathway towards mass preparation of two-dimensional materials and accelerates their development for diverse applications. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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13 pages, 9550 KiB

Open AccessArticle

Piranha Solution-Assisted Surface Engineering Enables Silicon Nanocrystals with Superior Wettability and Lithium Storage

by Tingting Li, Yangfan Li, Fan Zhang, Naiwen Liang, Jiang Yin, Haihong Zhao, Yahui Yang, Bo Chen and Lishan Yang

Crystals 2023, 13(7), 1127; https://doi.org/10.3390/cryst13071127 - 19 Jul 2023

Cited by 2 | Viewed by 2174

Abstract

Silicon anodes with a high theoretical capacity possess great potential applications in power batteries for electric vehicles, while their volume expansion always leads to crystal pulverization and electrode polarization. An ideal solution to alleviate such pulverization and polarization of silicon crystals is to [...] Read more.

Silicon anodes with a high theoretical capacity possess great potential applications in power batteries for electric vehicles, while their volume expansion always leads to crystal pulverization and electrode polarization. An ideal solution to alleviate such pulverization and polarization of silicon crystals is to simultaneously use nano-sized silicon crystals and introduce high viscosity and elasticity polymer binders. This work has achieved the adjustable introduction of hydroxyl groups to silicon nanocrystals under the optimal reaction temperature (e.g., 80 °C) and appropriate piranha solution composition (e.g., H₂SO₄/H₂O₂ = 3:1 v/v), ultimately forming an amorphous coating layer of ~1.3 nm on the silicon surface. The optimized silicon anode exhibits superior electrochemical performance (with an initial Coulombic efficiency of 85.5%; 1121.4 mA h g⁻¹ at 1 A g⁻¹ after 200 cycles) and improved hydrophilicity. The introduced hydroxyl groups significantly enhance the hydrophilicity of silicon in the electrolyte and the electrochemical activity of the silicon anodes. The hydroxyl groups achieve stronger bonding between silicon and polymer binders, ultimately improving the mechanical strength and stability of the electrode. The introduction of hydrophily functional groups on the surface of silicon crystals can be explored as an active strategy to solve the above issues. This surface engineering method could be extended to more fields of infiltrating silicon-based functional materials. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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13 pages, 3314 KiB

Open AccessArticle

Preparation of N, Cl Co-Doped Lignin Carbon Quantum Dots and Detection of Microplastics in Water

by Hao Zhao, Zishuai Jiang, Chengyu Wang and Yudong Li

Crystals 2023, 13(6), 983; https://doi.org/10.3390/cryst13060983 - 20 Jun 2023

Cited by 5 | Viewed by 2629

Abstract

The research on rapid and efficient detection of microplastics in water is still in its early stages. Fluorescence feature recognition represents an important and innovative approach to microplastic detection. While carbon quantum dots have been widely used in various environmental detection methods, their [...] Read more.

The research on rapid and efficient detection of microplastics in water is still in its early stages. Fluorescence feature recognition represents an important and innovative approach to microplastic detection. While carbon quantum dots have been widely used in various environmental detection methods, their use for detecting microplastics in water environments has been rarely reported. In this study, N and Cl co-doped carbon quantum dots were synthesized via a hydrothermal method. The heteroatom doping process endowed them with blue luminescence properties, and their adsorption for microplastics was improved through the introduction of positive and negative charges and intermolecular forces. By utilizing a combined mechanism of fluorescence and Rayleigh scattering, the detection of polystyrene microplastics with three different particle sizes was achieved. In the detection process, it exhibits excellent light stability. Notably, the nano-polystyrene exhibited a good nonlinear relationship within the range of 0.01 g/L to 0.001 g/L, with R² values of 0.923 and 0.980 and a detection limit of 0.4 mg/L. These findings provide a novel approach for the detection of nano microplastics. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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14 pages, 5189 KiB

Open AccessArticle

Graphene-Assembled Film-Based Reconfigurable Filtering Antenna with Enhanced Corrosion-Resistance

by Yueyue Hui, Haoran Zu, Rongguo Song, Huaqiang Fu, Kaolin Luo, Chao Tian, Bian Wu, Guan-Long Huang, Zongkui Kou, Xin Cheng and Daping He

Crystals 2023, 13(5), 747; https://doi.org/10.3390/cryst13050747 - 29 Apr 2023

Cited by 8 | Viewed by 1981

Abstract

Corrosion-resistance is the key to improve the reliability and service lifespan of highly integrated reconfigurable filtering antennae. However, the conventional methodology for corrosion prevention cannot achieve desired effects, due to the limited intrinsic corrosion-resistance capacity of traditional metal-based devices. Here, we developed a [...] Read more.

Corrosion-resistance is the key to improve the reliability and service lifespan of highly integrated reconfigurable filtering antennae. However, the conventional methodology for corrosion prevention cannot achieve desired effects, due to the limited intrinsic corrosion-resistance capacity of traditional metal-based devices. Here, we developed a reconfigurable filtering antenna based on graphene assembled film (GAF), featuring significant corrosion-resistance enhancement. The GAF-based antenna exhibits comparable electrical performance when compared with a copper-based antenna, and can flexibly switch between two working modes, including ultra-wideband (UWB, 2.8–11 GHz) and narrowband filtering (NBF, 3.23–3.77 GHz). To further demonstrate the of the corrosion-resistance of GAF, a salt spray corrosion test found that the GAF-based antenna exhibits steady electrical properties after corrosion for over 336 h, while the copper-based antenna shows rapid performance degradation. The simulated and experimental results are in agreement, indicating that the proposed GAF reconfigurable filtering antenna can be applied to broader application prospects in communication systems, especially in severe environments. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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Review

Jump to: Research

16 pages, 2894 KiB

Open AccessReview

Absorption of Light in Vertical III-V Semiconductor Nanowires for Solar Cell and Photodetector Applications

by Nicklas Anttu

Crystals 2023, 13(9), 1292; https://doi.org/10.3390/cryst13091292 - 22 Aug 2023

Cited by 7 | Viewed by 1510

Abstract

Vertical III-V semiconductor nanowires have shown promising absorption of light for solar cell and photodetector applications. The absorption properties can be tuned through the choice of III-V materials and geometry of the nanowires. Here, we review the recent progress in the design of [...] Read more.

Vertical III-V semiconductor nanowires have shown promising absorption of light for solar cell and photodetector applications. The absorption properties can be tuned through the choice of III-V materials and geometry of the nanowires. Here, we review the recent progress in the design of the absorption properties of both individual nanowires and nanowire arrays. Future directions for the research field are proposed. Full article

(This article belongs to the Special Issue Emerging Low-Dimensional Materials II)

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