Current and Potential Characterization on InAs Wires by Contact-mode AFM and Kelvin Probe Force Microscopy

Shiano Ono, Misaichi Takeuchi* and Takuji Takahashi

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

We fabricated InAs wires on GaAs giant step structures, and AFM measurements were performed on their surfaces by two methods; one was current detection by contact-mode AFM, and the other was surface potential measurements by Kelvin probe force microscopy (KFM). In the current detection method, the regions where the current flowed were distributed along the step edges, and these regions agreed well with the expected distribution of InAs. This result confirms that the InAs wires were formed along the GaAs giant step edges. The KFM measurements showed that the potential value became more negative along the step edges, where the InAs wires were expected to be formed. Therefore, we can conclude that the surface potential of the InAs wires is more negative than the surrounding GaAs, which may result from the electron accumulation in the InAs wires.