STM-MIDAS · Scanning Tunneling Microscopy - Modeling Defects and Adsorbates onSemiconductors and Insulating Films

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Project objective

This research deals with modeling of Scanning Tunneling Microscopy (STM) and Spectroscopies (STS) in studying defects and adsorbates on ultrathin insulating films and semiconductor surfaces. Theoretical modeling of STM is a necessary part in interpreting e xperimental data, and also in planning future experiments. The objectives of this research project are twofold. First, this project will serve as further training for a post doctoral researcher, Dr. Sami Paavilainen, to prepare working as an independent re searcher. The second objective is to develop and utilize different methods in analyzing the STS and STM experiments. The methods will include density functional theory calculations, tight-binding model and models for elastic and inelastic tunneling in diff erent tunneling junctions.Insulating films on metal surfaces can be studied with STM if they are thin enough. Thin insulating films are also interesting due to their prospects in nanotechnology where the decoupling of adsorbates from the metal could be uti lized, e.g., in production of nanocircuits. The modeling of STS of these films is complicated, since defect and adsorbate states form a double barrier tunneling junction.For semiconductors, our interest lies in the Cross-sectional STM (X-STM) which allows one to study formation of defects and segregation in epitaxial growth of compound semiconductors. Because STM probes contours of a constant LDOS, heterointerfaces made of different types of atoms on the opposite sides are revealed by image contrast. Modeli ng these subtle effects requires also combining different methods.The group has a wide cooperation with top-class experimental STM groups in Europe. In addition, collaboration inside the local university has a significant role in this project.

Original text from CORDIS.

Participants

• TAMPERE UNIVERSITY OF TECHNOLOGY · TAMPERECoordinatorFinland

Links

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