Topical Review|54 Article(s)
Mass transfer techniques for large-scale and high-density microLED arrays
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Inorganic-based micro light-emitting diodes (microLEDs) offer more fascinating properties and unique demands in next-generation displays. However, the small size of the microLED chip (1-100 μm) makes it extremely challenging for high efficiency and low cost to accurately, selectively, integrate millions of microLED chips. Recent impressive technological advances have overcome the drawbacks of traditional pick-and-place techniques when they were utilized in the assembly of microLED display, including the most broadly recognized laser lift-off technique, contact micro-transfer printing (μTP) technique, laser non-contact μTP technique, and self-assembly technique. Herein, we firstly review the key developments in mass transfer technique and highlight their potential value, covering both the state-of-the-art devices and requirements for mass transfer in the assembly of the ultra-large-area display and virtual reality glasses. We begin with the significant challenges and the brief history of mass transfer technique, and expand that mass transfer technique is composed of two major techniques, namely, the epitaxial Lift-off technique and the pick-and-place technique. The basic concept and transfer effects for each representative epitaxial Lift-off and pick-and-place technique in mass transfer are then overviewed separately. Finally, the potential challenges and future research directions of mass transfer are discussed.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 4, 42005 (2022)
Advances in selective laser sintering of polymers
Wei Han, Lingbao Kong, and Min Xu
Polymers are widely used materials in aerospace, automotive, construction, medical devices and pharmaceuticals. Polymers are being promoted rapidly due to their ease of manufacturing and improved material properties. Research on polymer processing technology should be paid more attention to due to the increasing demand for polymer applications. Selective laser sintering (SLS) uses a laser to sinter powdered materials (typical polyamide), and it is one of the critical additive manufacturing (AM) techniques of polymer. It irradiates the laser beam on the defined areas by a computer-aided design three-dimensional (3D) model to bind the material together to create a designed 3D solid structure. SLS has many advantages, such as no support structures and excellent mechanical properties resembling injection moulded parts compared with other AM methods. However, the ability of SLS to process polymers is still affected by some defects, such as the porous structure and limited available types of SLS polymers. Therefore, this article reviews the current state-of-the-art SLS of polymers, including the fundamental principles in this technique, the SLS developments of typical polymers, and the essential process parameters in SLS. Furthermore, the applications of SLS are focused, and the conclusions and perspectives are discussed.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 4, 42002 (2022)
The advanced multi-functional carbon dots in photoelectrochemistry based energy conversion
Yunjie Zhou, Fan Liao, Yang Liu, and and Zhenhui Kang
Carbon dots (CDs), as a unique zero-dimensional member of carbon materials, have attracted numerous attentions for their potential applications in optoelectronic, biological, and energy related fields. Recently, CDs as catalysts for energy conversion reactions under multi-physical conditions such as light and/or electricity have grown into a research frontier due to their advantages of high visible light utilization, fast migration of charge carriers, efficient surface redox reactions and good electrical conductivity. In this review, we summarize the fabrication methods of CDs and corresponding CD nanocomposites, including the strategies of surface modification and heteroatom doping. The properties of CDs that concerned to the photo- and electro-catalysis are highlighted and detailed corresponding applications are listed. More importantly, as new non-contact detection technologies, transient photo-induced voltage/current have been developed to detect and study the charge transfer kinetics, which can sensitively reflect the complex electron separation and transfer behavior in photo-/electro-catalysts. The development and application of the techniques are reviewed. Finally, we discuss and outline the major challenges and opportunities for future CD-based catalysts, and the needs and expectations for the development of novel characterization technologies.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 4, 42001 (2022)
Advances in the design and manufacturing of novel freeform optics
Sumit Kumar, Zhen Tong, and Xiangqian Jiang
Freeform optics has become the most prominent element of the optics industry. Advanced freeform optical designs supplementary to ultra-precision manufacturing and metrology techniques have upgraded the lifestyle, thinking, and observing power of existing humans. Imaginations related to space explorations, portability, accessibility have also witnessed sensible in today’s time with freeform optics. Present-day design methods and fabrications techniques applicable in the development of freeform optics and the market requirements are focussed and explained with the help of traditional and non-traditional optical applications. Over the years, significant research is performed in the emerging field of freeform optics, but no standards are established yet in terms of tolerances and definitions. We critically review the optical design methods for freeform optics considering the image forming and non-image forming applications. Numerous subtractive manufacturing technologies including figure correction methods and metrology have been developed to fabricate extreme modern freeform optics to satisfy the demands of various applications such as space, astronomy, earth science, defence, biomedical, material processing, surveillance, and many more. We described a variety of advanced technologies in manufacturing and metrology for novel freeform optics. Next, we also covered the manufacturing-oriented design scheme for advanced optics. We conclude this review with an outlook on the future of freeform optics design, manufacturing and metrology.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 3, 32004 (2022)
Ultrafast synthetic strategies under extreme heating conditions toward single-atom catalysts
Guanchao He, Minmin Yan, Haisheng Gong, Huilong Fei, and Shuangyin Wang
Dispersing atomic metals on substrates provides an ideal method to maximize metal utilization efficiency, which is important for the production of cost-effective catalysts and the atomic-level control of the electronic structure. However, due to the high surface energy, individual single atoms tend to migrate and aggregate into nanoparticles during preparation and catalytic operation. In the past few years, various synthetic strategies based on ultrafast thermal activation toward the effective preparation of single-atom catalysts (SACs) have emerged, which could effectively solve the aggregation issue. Here, we highlight and summarize the latest developments in various ultrafast synthetic strategy with rapid energy input by heating shockwave and instant quenching for the synthesis of SACs, including Joule heating, microwave heating, solid-phase laser irradiation, flame-assisted method, arc-discharge method and so on, with special emphasis on how to achieve the uniform dispersion of single metal atoms at high metal loadings as well as the suitability for scalable production. Finally, we point out the advantages and disadvantages of the ultrafast heating strategies as well as the trends and challenges of future developments.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 3, 32003 (2022)
Near-field radiative heat transfer in hyperbolic materials
Ruiyi Liu, Chenglong Zhou, Yong Zhang, Zheng Cui, Xiaohu Wu, and Hongliang Yi
In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer (NFRHT) with super-Planckian phenomena has gradually shown great potential for applications in efficient and ultrafast thermal modulation and energy conversion. Recently, hyperbolic materials, an important class of anisotropic materials with hyperbolic isofrequency contours, have been intensively investigated. As an exotic optical platform, hyperbolic materials bring tremendous new opportunities for NFRHT from theoretical advances to experimental designs. To date, there have been considerable achievements in NFRHT for hyperbolic materials, which range from the establishment of different unprecedented heat transport phenomena to various potential applications. This review concisely introduces the basic physics of NFRHT for hyperbolic materials, lays out the theoretical methods to address NFRHT for hyperbolic materials, and highlights unique behaviors as realized in different hyperbolic materials and the resulting applications. Finally, key challenges and opportunities of the NFRHT for hyperbolic materials in terms of fundamental physics, experimental validations, and potential applications are outlined and discussed.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 3, 32002 (2022)
Optical wafer defect inspection at the 10 nm technology node and beyond
Jinlong Zhu, Jiamin Liu, Tianlai Xu, Shuai Yuan, Zexu Zhang, Hao Jiang, Honggang Gu, Renjie Zhou, and Shiyuan Liu
The growing demand for electronic devices, smart devices, and the Internet of Things constitutes the primary driving force for marching down the path of decreased critical dimension and increased circuit intricacy of integrated circuits. However, as sub-10 nm high-volume manufacturing is becoming the mainstream, there is greater awareness that defects introduced by original equipment manufacturer components impact yield and manufacturing costs. The identification, positioning, and classification of these defects, including random particles and systematic defects, are becoming more and more challenging at the 10 nm node and beyond. Very recently, the combination of conventional optical defect inspection with emerging techniques such as nanophotonics, optical vortices, computational imaging, quantitative phase imaging, and deep learning is giving the field a new possibility. Hence, it is extremely necessary to make a thorough review for disclosing new perspectives and exciting trends, on the foundation of former great reviews in the field of defect inspection methods. In this article, we give a comprehensive review of the emerging topics in the past decade with a focus on three specific areas: (a) the defect detectability evaluation, (b) the diverse optical inspection systems, and (c) the post-processing algorithms. We hope, this work can be of importance to both new entrants in the field and people who are seeking to use it in interdisciplinary work.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 3, 32001 (2022)
The fabrication, characterization and functionalization in molecular electronics
Yi Zhao, Wenqing Liu, Jiaoyang Zhao, Yasi Wang, Jueting Zheng, Junyang Liu, Wenjing Hong, and Zhong-Qun Tian
Developments in advanced manufacturing have promoted the miniaturization of semiconductor electronic devices to a near-atomic scale, which continuously follows the ‘top-down’ construction method. However, huge challenges have been encountered with the exponentially increased cost and inevitably prominent quantum effects. Molecular electronics is a highly interdisciplinary subject that studies the quantum behavior of electrons tunneling in molecules. It aims to assemble electronic devices in a ‘bottom-up’ manner on this scale through a single molecule, thereby shedding light on the future design of logic circuits with new operating principles. The core technologies in this field are based on the rapid development of precise fabrication at a molecular scale, regulation at a quantum scale, and related applications of the basic electronic component of the ‘electrode-molecule-electrode junction’. Therefore, the quantum charge transport properties of the molecule can be controlled to pave the way for the bottom-up construction of single-molecule devices. The review firstly focuses on the collection and classification of the construction methods for molecular junctions. Thereafter, various characterization and regulation methods for molecular junctions are discussed, followed by the properties based on tunneling theory at the quantum scale of the corresponding molecular electronic devices. Finally, a summary and perspective are given to discuss further challenges and opportunities for the future design of electronic devices.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 2, 22003 (2022)
Intermolecular and surface forces in atomic-scale manufacturing
Xin Hou, Jingyang Li, Yuanzhe Li, and Yu Tian
Atomic and close-to-atomic scale manufacturing (ACSM) aims to provide techniques for manufacturing in various fields, such as circuit manufacturing, high energy physics equipment, and medical devices and materials. The realization of atomic scale material manipulation depending on the theoretical system of classical mechanics faces great challenges. Understanding and using intermolecular and surface forces are the basis for better designing of ACSM. Transformation of atoms based on scanning tunneling microscopy or atomic force microscopy (AFM) is an essential process to regulate intermolecular interactions. Self-assemble process is a thermodynamic process involving complex intermolecular forces. The competition of these interaction determines structure assembly and packing geometry. For typical nanomachining processes including AFM nanomachining and chemical mechanical polishing, the coupling of chemistry and stress (tribochemistry) assists in the removal of surface atoms. Furthermore, based on the principle of triboelectrochemistry, we expect a further reduction of the potential barrier, and a potential application in high-efficiency atoms removal and fabricating functional coating. Future fundamental research is proposed for achieving high-efficiency and high-accuracy manufacturing with the aiding of external field. This review highlights the significant contribution of intermolecular and surface forces to ACSM, and may accelerate its progress in the in-depth investigation of fundamentals.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 2, 22002 (2022)
Triply periodic minimal surface (TPMS) porous structures: from multi-scale design, precise additive manufacturing to multidisciplinary applications
Jiawei Feng, Jianzhong Fu, Xinhua Yao, and Yong He
Inspired by natural porous architectures, numerous attempts have been made to generate porous structures. Owing to the smooth surfaces, highly interconnected porous architectures, and mathematical controllable geometry features, triply periodic minimal surface (TPMS) is emerging as an outstanding solution to constructing porous structures in recent years. However, many advantages of TPMS are not fully utilized in current research. Critical problems of the process from design, manufacturing to applications need further systematic and integrated discussions. In this work, a comprehensive overview of TPMS porous structures is provided. In order to generate the digital models of TPMS, the geometry design algorithms and performance control strategies are introduced according to diverse requirements. Based on that, precise additive manufacturing methods are summarized for fabricating physical TPMS products. Furthermore, actual multidisciplinary applications are presented to clarify the advantages and further potential of TPMS porous structures. Eventually, the existing problems and further research outlooks are discussed.
International Journal of Extreme Manufacturing
  • Publication Date: Jan. 01, 2022
  • Vol. 4, Issue 2, 22001 (2022)