Surface electronic properties on GaAs covered by InAs nano-wires studied by light-illuminated STM

Kan Takada¹, Misaichi Takeuchi² and Takuji Takahashi¹

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

We investigated the electronic properties on GaAs covered by InAs nano-wires by light-illuminated STM. The InAs wires were formed along the giant step edges on (110) GaAs vicinal substrates. In the photoinduced current image at the sample bias of -2V and the laser wavelength of 800nm, we can clearly distinguish the InAs wires from the bared GaAs region. We attribute this contrast between the InAs wires and GaAs to the degree of surface depletion, that is, the bared surface of GaAs is more depleted than the InAs wire-covered GaAs.