STM-Induced Luminescence for Alkanethiol Films on Au(111) Surface

R. Nishitani a , Y. Tateishi b , H. Arakawa b , A. Kasuya c and K. Sumiyama d a Dept. of Electrical and Electronics Engineering, Univ. of the Ryukyus Okinawa 903-0213, Japan b Dept. of Computer Sciences and Electronics, Kyushu Institute of Technology Iizuka, Fukuoka 820-8502, Japan c Center for Interdisciplinary Research, Tohoku Univ. Aoba-ku, Sendai 980-8578, Japan d Dept. of Materials Science and Engineering, Nagoya Institute of Technology Showa-ku, Nagoya 466-8535, Japan

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STM-induced luminescence spectra for organic molecule adsorbed Au(111) surfaces were studied, and the influence of STM-tip alloy material on the emission spectra was measured. We observed the STM-tip dependent emission spectra of Au(111). The characteristics of the spectra with Pt--Ir alloy(20%) tip are interpreted in terms of the one-mode type and two-mode type depending on the composition rates. We measured the emission spectra for two different types of molecules, decanethiol and octanedithiol, which have different adsorption structures. The emission spectra for the octanedithiol films were compared with the spectra from clean gold films and the decanethiol films. A spectral change of Au(111) due to adsorption of octanedithiol molecules on Au(111) was observed in the spectral range from 700 through 780nm while not for the adsorption of decanethiol molecules. The spectral change due to adsorption of octanedithiol molecules is compared with the STS measurements.

DOI: 10.12693/APhysPolA.104.269 PACS numbers: 68.37.Ef, 73.20.Mf, 78.68.+m, 68.43.Hn