Studying the Surface Conductivity of a Thallium Bilayer on Si(111) Substrate after Adsorption of Lithium and Rubidium

Abstract

Changes in the state of a thallium bilayer on Si(111) substrate, Si(111)6 × 6–Tl, after adsorption of lithium and rubidium were studied using low-energy electron-diffraction and four-point probe-conductivity measurements. New surface reconstructions 5 × 1 and \(5\sqrt 3 \times 5\sqrt 3 \) were observed after the adsorption of lithium, and 2 × 2 and \(\sqrt 3 \times \sqrt 3 \) reconstructions appeared after the adsorption of rubidium. The surface conductivity of silicon substrates was studied as a function of the dose of deposited adsorbate. It is established that the formation of both 5 × 1 and 2 × 2 reconstructions retains the conducting properties of a two-dimensional channel constituted by the thallium bilayer.