Aluminum Nanostructures on Si(100)-2×1: STM/STS Study

Aluminum forms various structures on Si(100)-2×1. The most important of these are one-dimensional chains which are formed at room temperature and Si-Al clusters which can form c(4×12) reconstruction at temperature about 500 °C. STS spectra were measured above Al chains, in its close surroundings and above typical defects which are formed on the chains. One type of defect which appears at temperatures from 200 to 300 °C has a metallic tunneling spectrum. Si dimers adjacent to Al chains have tunneling spectra slightly different from a clean silicon. It indicates that they can have different reactivity. The clusters forming the c(4×12) reconstruction have semiconductive tunneling spectra with a band gap about 1.2 eV.