Kelvin probe force microscopy on InAs nanostructures

T. Takahashi¹, S. Ono¹, and M. Takeuchi²

1) Institute of Industrial Science, University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
2) Semiconductors Laboratory, The Institute of Physical and Chemical Research
2-1 Hirosawa, Wako, Saitama 351-0198, Japan

We can form InAs nanostructures like thin films or wires on (110) GaAs substrates by controlling the growth conditions, such as the grown amount of InAs, the growth temperature, the substrate orientations, and so on. Surface potential distributions on such thin films and wires were studied by Kelvin probe force microscopy (KFM).
On the thin films, the surface potential strongly depends on the surface geometry. When the surface is corrugated and has some terraces, the potential at the terrace edge is more negative than the top surface of the terrace. In addition, the thicker film has more negative surface potential. On the other hand, the InAs wires formed along the GaAs giant step edges have negative surface potential compared with the surrounding GaAs. We can attribute the whole results to the electron accumulation near the InAs surfaces owing to the surface Fermi level pinning inside the conduction band of InAs.