Atomic scale engineering of materials and interfaces has become increasingly important in material manufacturing. Atomic layer deposition (ALD) is a technology that can offer many unique properties to achieve atomic-scale material manufacturing controllability. Herein, we discuss this ALD technology for its applications, attributes, technology status and challenges. We envision that the ALD technology will continue making significant contributions to various industries and technologies in the coming years.

Zero-emission eco-friendly vehicles with partly or fully electric powertrains have exhibited rapidly increased demand for reducing the emissions of air pollutants and improving the energy efficiency. Advanced catalytic and energy materials are essential as the significant portions in the key technologies of eco-friendly vehicles, such as the exhaust emission control system, power lithium ion battery and hydrogen fuel cell. Precise synthesis and surface modification of the functional materials and electrodes are required to satisfy the efficient surface and interface catalysis, as well as rapid electron/ion transport. Atomic layer deposition (ALD), an atomic and close-to-atomic scale manufacturing method, shows unique characteristics of precise thickness control, uniformity and conformality for film deposition, which has emerged as an important technique to design and engineer advanced catalytic and energy materials. This review has summarized recent process of ALD on the controllable preparation and modification of metal and oxide catalysts, as well as lithium ion battery and fuel cell electrodes. The enhanced catalytic and electrochemical performances are discussed with the unique nanostructures prepared by ALD. Recent works on ALD reactors for mass production are highlighted. The challenges involved in the research and development of ALD on the future practical applications are presented, including precursor and deposition process investigation, practical device performance evaluation, large-scale and efficient production, etc.

The flexible pressure sensor has been credited for leading performance including higher sensitivity, faster response/recovery, wider detection range and higher mechanical durability, thus driving the development of novel sensing materials enabled by new processing technologies. Using atomic layer infiltration, Pt nanocrystals with dimensions on the order of a few nanometers can be infiltrated into the compressible lamellar structure of Ti₃C₂T_x MXene, allowing a modulation of its interlayer spacing, electrical conductivity and piezoresistive property. The flexible piezoresistive sensor is further developed from the Pt-infiltrated MXene on a paper substrate. It is demonstrated that Pt infiltration leads to a significant enhancement of the pressure-sensing performance of the sensor, including increase of sensitivity from 0.08 ​kPa⁻¹ to 0.5 ​kPa⁻¹, extension of detection limit from 5 ​kPa to 9 ​kPa, decrease of response time from 200 ​ms to 20 ​ms, and reduction of recovery time from 230 ​ms to 50 ​ms. The mechanical durability of the flexible sensor is also improved, with the piezoresistive performance stable over 1000 cycles of flexure fatigue. The atomic layer infiltration process offers new possibilities for the structure modification of MXene for advanced sensor applications.

Surface modification for micro-nanoparticles at the atomic and close-to-atomic scales is of great importance to enhance their performance in various applications, including high-volume battery, persistent luminescence, etc. Fluidized bed atomic layer deposition (FB-ALD) is a promising atomic-scale manufacturing technology that offers ultrathin films on large amounts of particulate materials. Nevertheless, nanoparticles tend to agglomerate due to the strong cohesive forces, which is much unfavorable to the film conformality and also hinders their real applications. In this paper, the particle fluidization process in an ultrasonic vibration-assisted FB-ALD reactor is numerically investigated from micro-scale to macro-scale through the multiscale computational fluid dynamics and discrete element method (CFD-DEM) modeling with experimental verification. Various vibration amplitudes and frequencies are investigated in terms of their effects on the fluid dynamics, distribution of particle velocity and solid volume fraction, as well as the size of agglomerates. Results show that the fluid turbulent kinetic energy, which is the key power source for the particles to obtain the kinetic energy for overcoming the interparticle agglomeration forces, can be strengthened obviously by the ultrasonic vibration. Besides, the application of ultrasonic vibration is found to reduce the mean agglomerate size in the FB. This is bound to facilitate the heat transfer and precursor diffusion in the entire FB-ALD reactor and the agglomerates, which can largely shorten the coating time and improve the film conformality as well as precursor utilization. The simulation results also agree well with our battery experimental results, verifying the validity of the multiscale CFD-DEM model. This work has provided momentous guidance to the mass manufacturing of atomic-scale particle coating from lab-scale to industrial applications.

In the past decades, Moore’s law drives the semiconductor industry to continuously shrink the critical size of transistors down to 7 nm. As transistors further downscaling to smaller sizes, the law reaches its limitation, and the increase of transistors density on the chip decelerates. Up to now, extreme ultraviolet lithography has been used in some key steps, and it is facing alignment precision and high costs for high-volume manufacturing. Meanwhile, the introduction of new materials and 3D complex structures brings serious challenges for top-down methods. Thus, bottom-up schemes are believed to be necessary methods combined with the top-down processes. In this article, atomic level deposition methods are reviewed and categorized to extend Moore’s law and beyond. Firstly, the deposition brings lateral angstrom resolution to the vertical direction as well as top-down etching, such as double patterning, transfer of nanowires, deposition of nanotubes, and so on. Secondly, various template-assisted selective deposition methods including dielectric templates, inhibitors and correction steps have been utilized for the alignment of 3D complex structures. Higher resolution can be achieved by inherently selective deposition, and the underlying selective mechanism is discussed. Finally, the requirements for higher precision and efficiency manufacturing are also discussed, including the equipment, integration processes, scale-up issues, etc. The article reviews low dimensional manufacturing and integration of 3D complex structures for the extension of Moore’s law in semiconductor fields, and emerging fields including but not limited to energy, catalysis, sensor and biomedicals.