Molecular beam epitaxy of bilayer Bi(111) films on topological insulator Bi2Te3: A scanning tunneling microscopy study

We report on molecular beam epitaxy growth of bilayer Bi(111) films on topological insulator Bi2Te3. In situ scanning tunneling microscopy/spectroscopy shows that Bi growth mode changes from quasi bilayer-by-bilayer to step-flow with increasing substrate temperature. Bilayer Bi(111) exhibits an electron donor behavior, causing an 80 meV downshift of the Dirac point of Bi2Te3. Local work function difference between the bilayer films and Bi2Te3 films is measured to be 390 meV. Based on the observations, we propose a schematic energy-band diagram which reveals band bending effect at the Bi/Bi2Te3 interface. Our work paves a way to explore the exotic topological properties of bilayer islands and thin films of Bi. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4747715]