Uncovering the Self-Organized Nanowires on Au-Modified Ge(001) Surfaces

• Published in: Journal of physical chemistry. C 2021-12, Vol.125 (50), p.27876-27883
• Main Authors: Lyu, Jing, Wong, Zicong Marvin, Sun, Haicheng, Yang, Shuo-Wang, Xu, Guo Qin
• Format: Article
• Language: English
• Subjects: C: Physical Properties of Materials and Interfaces
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.1c09171

A fundamental understanding of the atomic and electronic structures of metallic nanowires (NWs) on semiconductors is critical for micro- or molecular electronics. The deposition of Au atoms on Ge(001) surfaces can trigger the self-assembly of atomic NWs extending for hundreds of nanometers, and these NWs raised much controversy on their atomic/electronic configurations. In this work, different types of NWs were characterized on Au/Ge(001) surfaces via scanning tunneling microscopy (STM). Combined with density functional theory (DFT) calculations, the atomic structures of Au-induced NWs on Ge(001) surfaces were decoded, including the NWs-H/L and complex chevron and zigzag (V–W) reconstructions, where simulated V–W patterns at filled states transform to triplets at empty states. Moreover, a quasi-one-dimensional (1D) electronic behavior and anisotropic two-dimensional (2D) electronic states are uncovered in the Au–Ge-modified-dimer-row (AGMDR) and Au-NWs-in-trench (ANT) models, respectively, reconciling the previous controversy about electronic behaviors of NWs on Au/Ge(001) surfaces. Because of the quantum instability, 1D electron systems undergo a transition from metallic to nonconducting, while the atomic NWs (i.e., NWs-H and NWs-L) in the ANT model are metallic, rendering them good conductive channels for micro- or molecular electronics. Our findings provide insights into ascertaining the atomic structures of self-assembled NWs and understanding the discrepancies of the Au/Ge(001) material system.