Fabrication and electric measurements of nanostructures inside transmission electron microscope

Advanced In Situ TEM Microchip with Excellent Temperature Uniformity and High Spatial Resolution

Transmission electron microscopy (TEM) is a highly effective method for scientific research, providing comprehensive analysis and characterization. However, traditional TEM is limited to observing static material structures at room temperature within a high-vacuum environment. To address this limitation, a microchip was developed for in situ TEM characterization, enabling the real-time study of material structure evolution and chemical process mechanisms. This microchip, based on microelectromechanical System (MEMS) technology, is capable of introducing multi-physics stimulation and can be used in conjunction with TEM to investigate the dynamic changes of matter in gas and high-temperature environments. The microchip design ensures a high-temperature uniformity in the sample observation area, and a system of tests was established to verify its performance. Results show that the temperature uniformity of 10 real-time observation windows with a total area of up to 1130 μm² exceeded 95%, and the spatial resolution reached the lattice level, even in a flowing atmosphere of 1 bar.

A platform for in-situ multi-probe electronic measurements and modification of nanodevices inside a transmission electron microscope

We developed a new platform that enables in-situ four-probe electronic measurements, in-situ three-probe field-effect measurements, nanomanipulation, and in-situ modification of nanodevices inside a transmission electron microscope (TEM). The platform includes a specially designed chip-holder and a silicon (Si) chip with suspended metal electrodes. The chip-holder can hold one Si chip with a size up to 3 mm × 3 mm and provides four electrical connections that can be connected to the micrometer-sized electrodes on the Si chip by wire-bonding. The other side of the electrical connections on the chip-holder is connected to the electronic instruments outside the TEM through a commercial Nanofactory SPM-TEM holder. The Si chip with suspended metal electrodes on one of its edges was fabricated by lithography and wet etching. Carbon nanotubes (CNTs), InAs nanowires, and tungsten disulfide nanowires were placed to stride over and connect to the suspended electrodes on the Si chip by nanomanipulations inside a scanning electron microscope (SEM). By using the platform, I-V curves of an individual single-walled CNT connecting to four electrodes were in-situ measured between any two of the four suspended electrodes, and a high-resolution TEM image of the same CNT was obtained. Furthermore, four-terminal I-V measurement on an InAs nanowire was achieved on this platform, and with a movable probe used as a gate electrode, field-effect measurement on the same InAs nanowire device was accomplished in SEM. In addition, by using the movable probe on the SPM-TEM holder, we could further in-situ modify nanomaterial and nanodevices. The present work demonstrates a method that allows a direct correlation between the atomic-level structure and the electronic property of nanomaterials or nanodevices whose structure can be further modified in-situ.

Self-healing of bended WS2 nanotubes and its effect on the nanotube's properties

Individual WS(2) nanotubes (NTs) were bended and released in-situ inside a transmission electron microscope. Kinks appeared in the NTs suddenly during the bending process. Shell distortion, shell breaking and rotation of broken shells were observed in these kinks. Spontaneous self-healing and focused electron beam-assisted healing of the structure were observed after the load was removed. More importantly, the strength and electrical conductivity of the NTs were also restored to their original level when the structure recovered.