We have developed a unique tensile testing system using MEMS technology that enables direct measurement of the mechanical strength of nanomaterials inside a field-emission scanning electron microscope (SEM). Our custom MEMS devices incorporate electrostatic actuators and capacitive sensors, allowing in situ tensile tests on nanowire specimens within a modified SEM chamber.
Materials tested include carbon nanotubes, silicon nanowires, insulating nanofilms, and ultra-hard nanorods. Our work on silicon nanowires includes experimental evaluation of FIB-induced damage and the effects of vacuum annealing. Recently, we successfully measured the Young’s modulus and tensile strength of single-walled carbon nanotubes (SWCNTs) with diameters as small as 1–3 nm, establishing correlations between their structure and mechanical properties.

We develop a variety of original experimental techniques for evaluating thin films and microstructures. These include custom-made systems for uniaxial/in-plane biaxial tensile testing, Poisson's ratio measurement, in-SEM tensile testing, and strength testing of micro rods with bonded joints. We also conduct complex mechanical testing (tension, bending, torsion) of MEMS structures and shock testing.
Materials evaluated include silicon-based films, metal films, and polymer thin films. We have measured properties such as Young’s modulus, Poisson’s ratio, fracture strength, bonding strength, creep, stress relaxation, and fatigue.
Recent studies include applying our original testing systems for stress loading on MEMS/IC devices and fatigue testing of thin films using MEMS resonators.

   

Using our custom-designed multi-source DC/RF sputtering system, we fabricate metal multilayers composed of alternating nanolayers of dissimilar metals (e.g., aluminum and nickel). When triggered externally, these multilayers undergo self-propagating exothermic reactions due to alloying, enabling rapid and localized heating.
Such materials hold promise as compact heat sources for solder bonding and other applications. We are also developing highly sensitive multilayers that react to the slightest mechanical stimulus (e.g., a tap with tweezers), and biocompatible variants for medical and semiconductor applications.

We conduct creative mechanics research by leveraging the unique functions of nanoparticles and the physical phenomena arising from their assemblies.
For example, we have developed nanoparticles with repeating structures of biocompatible materials (e.g., titanium and silica) that exhibit controlled heating behavior. We have also created face-centered cubic (FCC) arrays of silica nanoparticles to produce structural color, enabling strain sensing through color variation.
Other projects include fabricating crystalline silicon nanodots inside silicon oxide films via electron beam irradiation to explore unconventional modulation of mechanical and electrical properties.

Micro/Nano Electro-Mechanical Systems (MEMS/ NEMS) are micro/nanometer-scale ‘machines’ with a multitude of applications across automotive, aviation, sensing, electronic, communications, healthcare, and AI industries. We are particularly interested in MEMS/NEMS resonator devices, where high-frequency mechanical vibration of an integrated micro/nanostructure is utilized for emerging applications in ultrasensitive sensing, efficient information processing, high-frequency signal processing, etc. The attached photograph shows an ultrathin-Si NEMS resonator device (with a width of just 20 nm) that is capable of ultrawide electrostatic tuning of resonance frequency, nonlinearity, quality factor, etc. at the application stage. We are investigating their unique dynamic properties, discovering ways to employ them for novel applications in ultrasensitive sensing and reservoir computing. Our expertise encompasses design, simulation, theoretical modelling, microfabrication, and characterization of MEMS/NEMS devices using Si, diamond, graphene, and other materials. If you are a student interested in learning about this fascinating research area, or an entrepreneur, start-up, or potential industry partner looking to consult or collaborate, or a fellow academic researcher interested in joining forces, please reach out to us.

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Diamond is well-known as a gemstone, a symbol of eternal love and enviable wealth; it is also a very attractive material from the viewpoint of science and technology. Diamond offers a unique combination of excellent physical and chemical properties, unmatched by any other material. In addition, diamond’s excellent chemical stability and biocompatibility enable novel applications, particularly in harsh environments and healthcare. Moreover, nanoscale diamond can withstand an ultra-large elastic strain (~ 10%), which can facilitate a new class of ‘strain-engineered’ electronic devices. Thus, using diamond as a material for micro/nano-scale devices can enhance performance, reliability and extend their domain of application. However, diamond is a notoriously difficult material for micro-processing. We are investigating scalable methods for micro/nanometer-scale patterning and reactive-ion-etching of diamond for creating electronic and electromechanical devices using artificial diamond. We hope these efforts will lead to scalable fabrication and ubiquitous application of diamond devices in the future. If you are a student interested in learning about microfabrication of diamond devices, or an entrepreneur, start-up, or potential industry partner looking to consult or collaborate, or a fellow academic researcher interested in joining forces, please reach out to us.