Low-energy electron diffraction studies of Si(111)-(√3 × √3)R30°-Bi system: Observation and structural determination of two phases

• Published in: Surface science Vol. 261; no. 1; pp. 69 - 87
• Main Authors: Wan, K.J., Guo, T., Ford, W.K., Hermanson, J.C.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.1992; Amsterdam Elsevier Science; New York, NY
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Physics; Solid surfaces and solid-solid interfaces; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Crystal growth; Voltage current curve; Bismuth; LEED diffraction; Silicon; Experimental study; Auger electron spectrometry; Surface structure
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(92)90219-V

The initial epitaxial growth of Bi on a Si(111)-7 × 7 surface has been studied as a function of overlayer coverage and deposition conditions using low-energy electron diffraction (LEED) and Auger electron spectroscopy (AES). Experiments show for the first time that two equilibrium phases are formed in the growth process, each displaying a (√3 × √3)R30° LEED symmetry: an α-phase occurring at 1 3 ML Bi coverage and substrate temperature of 360° C, and a β-phase at 1 ML and 300°C. Quantitative structural information for each phase was determined by multiple scattering analysis of I- V curves. The analysis is facilitated by comparing LEED intensity data measured for each phase with calculated values using appropriate structural models. The T 4 geometry for the α-phase and a trimer geometry for the β-phase are revealed to be the “best” models; detailed atomic coordinates have been determined for each phase.