[OPTICAL REVIEW Vol. 16, No. 3 (2009) 269-273]
© 2009 The Optical Society of Japan

Visualization of Space Charge Field Effect on Excitons in a GaAs Quantum Dot by Near-Field Optical Wavefunction Mapping

Yoshiaki SUGIMOTO1, Nobuhiro TSUMORI1, Shintaro NOMURA2, and Toshiharu SAIKI1,3

1School of Integrated Design Engineering, Keio University, Yokohama 223-8522, Japan
2Institute of Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
3Kanagawa Academy of Science and Technology, Kawasaki 213-0012, Japan

(Received January 26, 2009; Accepted February 2, 2009)

Near-field photoluminescence (PL) imaging spectroscopy was used to investigate multi-exciton and charged-exciton states confined in a single GaAs interface fluctuation quantum dot. We determined the origin of peaks in the PL spectra by employing a wavefunction mapping technique. We observed distortion of the exciton wavefunction due to the electric field produced by an excess electron at a nearby confined state. Near-field wavefunction mapping was demonstrated to be a powerful tool for visualizing the local environment, which affects the emission properties of quantum dots.

Key words: photoluminescence imaging spectroscopy, interfacial fluctuation quantum dot, near-field scanning microscope, multi exciton, charged exciton, finite-difference time-domain calculation method