Growth and Atomic Arrangement of a Single Layer NaCl on Si(100)

• Main Authors: Chan-Yuen Chang, 張展源
• Other Authors: Deng-Sung Lin
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/10315957028272326878

碩士 === 國立交通大學 === 物理研究所 === 96 === In this study‚ the electronic structure and morphology of single 2D NaCl layer heteroepitaxially grown on Si(100) are investigated by using scanning tunneling microscopy (STM) at room temperature. Instead of the conventional method of depositing NaCl molecules on the surface of semiconductor directly‚ we expose the clean Si(100) surface to Cl2 forming Cl/Si(100)-2 × 1 structure first and then evaporate sodium atoms on the Cl-saturated Si(100)-2 × 1 surface. Atomic resolved STM images for NaCl on the surface allow us not only to obtain further insight into the STM imaging process but also to clarify the heteroepitaxial growth process. From the experiment results, we conclude that： (1)The arriving sodium atoms migrate on the Cl/Si(100)-2 × 1 surface, and then are captured at the edge of 2D NaCl islands. (2)If the amount of sodium atoms is less than that of single atomic NaCl layer, then the topmost chlorine-terminated silicon layer within 2D NaCl islands forms an in-phase zig-zag structure in order to relax the lattice constant mismatch between NaCl and Si efficiently. According to the STM images, we also suggest that the NaCl layer is transparent to electron tunneling. (3)Because a strong binding exists within single atomic NaCl layer, the interaction between NaCl and Si will be weaker than the former islands stage. Therefore, the single atomic NaCl layer is just like a carpet attached on Si(100) surface, and the occupied tunneling signal convert Si(100) surface states into NaCl states.