The growing implementation of nanotubes and nanowires in NEMS devices has made nano-scale characterization of mechanical properties more important. Unfortunately, it is difficult to examine the dynamic response of nanowires without concurrent imaging and manipulation. Hence, there is a need for a device that facilitates high-resolution imaging of nano-structures during mechanical characterization.
Traditionally, the Transmission Electron Microscope (TEM) has enabled imaging of nano-scale materials on the atomic level. Therefore a combination of TEM imaging with simultaneous force measurements would be very powerful. The main challenge for such an instrument is to make it small enough to fit in the millimeter sized pole gap of a TEM.
We have developed two force sensors, one for an in situ TEM-Nanoindenter system [1] and another for an in situ TEM-AFM [2] system. Both systems facilitate high resolution imaging via the TEM, whilst measuring the dynamic responses in micro and nano Newton range, respectively.
The systems are based on the TEM-STM side-entry specimen holder developed by Nanofactory Instruments [3] and are equipped with custom designed miniaturized MEMS force sensors using capacitive and piezoresistive detection. The positioning utilizes a compact 3D inertial sliding solution combined with the fine movement of a piezoelectric slider [4]. In both systems the MEMS force sensors are mounted in the front piece of the holders and the electrical connections are made with spring type contacts to avoid permanent soldering and enable easy mounting and replacement. The systems have been used to characterize nanowires and to measure adhesion forces [5]. The development and applications to nano-scale structures will be presented at the conference.
[1] A. Nafari, A. Danilov, H. Rödjegård, P. Enoksson and H. Olin, Sensors and Actuators A, v123-124 (2005) 44
[2] A. Nafari, D. Karlen, C. Rusu, K. Svensson, H. Olin, P. Enoksson, Proceedings of IEEE MEMS2007 ( 2007)
[3] Nanofactory Instruments, www.nanofactory.com
[4] K. Svensson, Y. Jompol, H. Olin and E. Olsson, Rev. Sci. Instr. 74 (2003) 4945
[5] Y. Takahashi, H. Hirakata and T. Kitamura, International Synopsium on Electronics Materials and Packaging (2005) pp. 55
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