Colloidal nanoparticles are being intensely pursued in current nanoscience research. Nanochemists are often frustrated by the well-known fact that no two nanoparticles are the same, which precludes the deep understanding of many fundamental properties of colloidal nanoparticles in which the total structures (core plus surface) must be known. Therefore, controlling nanoparticles with atomic precision and solving their total structures have long been major dreams for nanochemists. Recently, these goals are partially fulfilled in the case of gold nanoparticles, at least in the ultrasmall size regime (1–3 nm in diameter, often called nanoclusters). This review summarizes the major progress in the field, including the principles that permit atomically precise synthesis, new types of atomic structures, and unique physical and chemical properties of atomically precise nanoparticles, as well as exciting opportunities for nanochemists to understand very fundamental science of colloidal nanoparticles (such as the s...

Atomically Precise Colloidal Metal Nanoclusters and Nanoparticles: Fundamentals and Opportunities

Semiconductor nanowires (NWs) have been studied extensively for over two decades for their novel electronic, photonic, thermal, electrochemical and mechanical properties. This comprehensive review article summarizes major advances in the synthesis, characterization, and application of these materials in the past decade. Developments in the understanding of the fundamental principles of "bottom-up" growth mechanisms are presented, with an emphasis on rational control of the morphology, stoichiometry, and crystal structure of the materials. This is followed by a discussion of the application of nanowires in i) electronic, ii) sensor, iii) photonic, iv) thermoelectric, v) photovoltaic, vi) photoelectrochemical, vii) battery, viii) mechanical, and ix) biological applications. Throughout the discussion, a detailed explanation of the unique properties associated with the one-dimensional nanowire geometry will be presented, and the benefits of these properties for the various applications will be highlighted. The review concludes with a brief perspective on future research directions, and remaining barriers which must be overcome for the successful commercial application of these technologies.

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25th Anniversary Article: Semiconductor Nanowires – Synthesis, Characterization, and Applications

Sustainable Industry 4.0 framework: A systematic literature review identifying the current trends and future perspectives

Ultraviolet (UV) photodetection has drawn a great deal of attention in recent years due to a wide range of civil and military applications. Because of its wide band gap, low cost, strong radiation hardness and high chemical stability, ZnO are regarded as one of the most promising candidates for UV photodetectors. Additionally, doping in ZnO with Mg elements can adjust the bandgap largely and make it feasible to prepare UV photodetectors with different cut-off wavelengths. ZnO-based photoconductors, Schottky photodiodes, metal–semiconductor–metal photodiodes and p–n junction photodetectors have been developed. In this work, it mainly focuses on the ZnO and ZnMgO films photodetectors. We analyze the performance of ZnO-based photodetectors, discussing recent achievements, and comparing the characteristics of the various photodetector structures developed to date.

https://www.mdpi.com/1424-8220/10/9/8604/pdf

ZnO-Based Ultraviolet Photodetectors

Piezo-actuated stages have become more and more promising in nanopositioning applications due to the excellent advantages of the fast response time, large mechanical force, and extremely fine resolution. Modeling and control are critical to achieve objectives for high-precision motion. However, piezo-actuated stages themselves suffer from the inherent drawbacks produced by the inherent creep and hysteresis nonlinearities and vibration caused by the lightly damped resonant dynamics, which make modeling and control of such systems challenging. To address these challenges, various techniques have been reported in the literature. This paper surveys and discusses the progresses of different modeling and control approaches for piezo-actuated nanopositioning stages and highlights new opportunities for the extended studies.

Modeling and Control of Piezo-Actuated Nanopositioning Stages: A Survey

To minimize the size of a stage with more DOF motion, this paper concentrates on the design, manufacturing process and control of a 5DOF thin coplanar nanometer-scale stage with high accuracy and multiple DOF motion. This paper uses the features of a flexible structure to develop a 200 mm × 200 mm × 35 mm thin coplanar nanometer-scale stage with 5DOF that allows the increase or decrease of axis action in accordance with various needs. The flexible structure of the thin coplanar nanometer-scale stage includes a cylindrical flexible body and an arc flexible body. The thin coplanar nanometer-scale stage allows for three-translational and two-rotational motions and is provided with eight piezoelectric actuators—one on the X -axis, another on the Y -axis, and the others on the Z -axis. The displacement characteristics of the output member of the stage were measured with the built-in capacitive sensors. It also used an analysis and identification controller design method for piezoelectric actuated systems. From the results, it can be seen that the performance of this controller is good and 10 nm controlling error of the step input can be obtained. The controlling error of the rotational angle is about 0.004 arcsec.

http://nfudee.nfu.edu.tw/ezfiles/43/1043/img/198/6.pdf

A novel 5DOF thin coplanar nanometer-scale stage

In this paper, the mechanical response and deformation behavior of anodic aluminum oxide (AAO) were investigated using experimental nanoindentation and Vickers hardness tests. The results showed the contact angle for the nanoporous AAO specimen was 105° and the specimen exhibited hydrophobic behavior. The hardness and the fracture strength of AAO were discussed and a three-dimensional finite element model (FEM) was also conducted to understand the nanoindentation-induced mechanism.

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Physical Behavior of Nanoporous Anodic Alumina Using Nanoindentation and Microhardness Tests

A simple three-dimensional (3D) laser angle sensor for 3D measurement of small
				angles based on the diffraction theorem and on ray optics analysis is presented The
				possibility of using position-sensitive detectors and a reflective diffraction
				grating to develop a 3D angle sensor was investigated and a prototype 3D laser angle
				sensor was designed and built The system is composed of a laser diode, two
				position-sensitive detectors, and a reflective diffraction grating The diffraction
				grating, mounted upon the rotational center of a 3D rotational stage, divides an
				incident laser beam into several diffracted rays, and two position-sensitive
				detectors are set up for detecting the positions of ±1st-order diffracted rays
				According to the optical path relationship between the three angular motions and the
				output coordinates of the two position-sensitive detectors, the 3D angles can be
				obtained through kinematic analysis The experimental results show the feasibility
				of the proposed 3D laser angular sensor Use of this system as an instrument for
				high-resolution measurement of small-angle rotation is proposed

Simple three-dimensional laser angle sensor for three-dimensional small-angle measurement.

Molecular dynamics simulations are performed to study the plastic deformation, stress and chip formation of scratched multi-layered films. The results showed that stick–slip and work-hardening behaviors were observed during the scratching process. There was a pile-up of amorphous disordered debris atoms and shear rupture ahead of the probe and a clear side-flow on the lateral sides of the probe when the probe moved forward. Both the plastic energy and the adhesion increased with an increase in the scratching depth. The glide band of the interface was on the {111}〈110〉 slip system with a maximum width of the glide band of about 1 nm. The strain energy stored in the deformed structure caused a higher stress region in the material in front of the tool edge, with a maximum stress of about 10 GPa. In addition, the mechanical response and thermal softness phenomenon are discussed.

Nanoscratch behavior of multi-layered films using molecular dynamics

We propose a diffraction-type optical triangulation sensor based on the diffraction theorem and the laser triangulation method. The advantage of the proposed sensor is that it obtains not only the linear displacement of a moving object but also its three angular motion errors. The developed sensor is composed mainly of a laser source, two quadrant detectors, and a reflective diffraction grating. The reflective diffraction grating can reflect the incident laser beam into several diffractive rays, and two quadrant detectors were set up for detecting the position of 0- and +1-order diffraction rays. According to the optical triangulation relationship between the spatial incident angles of a laser beam and the output coordinates of two quadrant detectors, the displacement and the three angular motion errors of a moving object can be obtained simultaneously.

Chien-Hung Liu

Papers

A novel 5DOF thin coplanar nanometer-scale stage

Physical Behavior of Nanoporous Anodic Alumina Using Nanoindentation and Microhardness Tests

Simple three-dimensional laser angle sensor for three-dimensional small-angle measurement.

Nanoscratch behavior of multi-layered films using molecular dynamics

Development of a diffraction-type optical triangulation sensor.