Sang-Kee EAH,¹ Wonho JHE,¹ Toshiharu SAIKI² and Motoichi OHTSU²

¹Department of Physics, Seoul National University, Seoul 151-742, Korea, ²Kanagawa Academy of Science and Technology KSP East 408, 3-2-1, Sakado Takatsu-ku, Kawasaki, 213 Japan

(Received August 17, 1996; Accepted August 30, 1996)

We have measured surface photoluminescence properties of Si-doped bulk GaAs using a near-field scanning optical microscope. An apertured fiber probe tip is used as an emitter of excitation laser as well as a collector of luminescence from GaAs. Due to the Fabry-Perot etalon effect, the excitation laser is reflected or transmitted with an oscillation period of λ_He-Ne/2 as the gap between the tip and the GaAs surface varies. The luminescence from GaAs also varies with an oscillation period of λ_GaAs/2 due to the same etalon effect. Therefore, the intensity of luminescence light collected by the probe tip shows a beating between two oscillations of different periods. When the probe approaches the GaAs surface, the collected luminescence intensity increases due to tunneling of evanescent wave. On the other hand, when we collect the luminescence using a lens, the intensity also increases due to similar coupling of evanescent wave into propagating wave in spite of a shadowing effect of the wide metal coating.

Key words : near-field scanning optical microscopy, photoluminescence, GaAs, Fabry-Perot effect

*This paper was originally presented at the first Asia-Pacific Workshop on Near Field Optics, which was held on August 17 and 18, 1996 at Seoul Education and Culture Center, Seoul, Korea, organized by Condensed Matter Research Institute, Seoul National University.