Dresden 2017 – wissenschaftliches Programm

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MI: Fachverband Mikrosonden

MI 7: Poster: Microanalysis and Microscopy

MI 7.10: Poster

Mittwoch, 22. März 2017, 18:00–20:00, P4

Construction of Ambient Simultaneous Scanning Tunneling /Atomic Force Microscope (STM/AFM) — •Ipen Demirel, Ahmed Uluca, Majid Fazeli Jadidi, and Hakan Özgür Özer — Istanbul Technical University, Istanbul, Turkey

we constructed an ambient simultaneous STM/AFM using a fiber-optic interferometry setup for cantilever deflection detection. Simultaneous measurements of tunnel current, force, force gradient, tunnel barrier height and energy loss with high sensitivity is possible with our specially designed and modified STM/AFM. Our microscope consists of a home-built STM and AFM head, which implements a TiO2 coated fiber attached to a small tube piezo on a commercial micro-positioner, vibration isolation system and SPM control unit. The frequency spectrum was obtained to determine resonance and phase curves on various cantilevers (Si, W) by PLL card besides lock-in amplifier. Since, interference pattern shows power at the signal photo-diode versus cantilever displacement as sensitivity of the interferometer, the fiber is locked by the controller at the most sensitive point. Working in the off-resonance region and using very small lever oscillation amplitudes, we are able to keep the probe in tunneling range during most of the cycle in simultaneous AFM/STM operation. The microscope was tested in STM mode on gold surface and atomically flat terraces has been imaged. We also conducted frequency modulation AFM imaging on the same surface. We are going to study various 2-D surfaces such as graphene, Bi2Te3 by using the microscope in simultaneous mode in which all relevant channels of information are acquired.