Journal of Electron Spectroscopy and Related Phenomena, 29 (1983) 343-343 Elsevler Saentlfic Publishmg Company, Amsterdam - Prmted m The Netherlands 343 MULTICHANNEL RAMAN SPECTROSCOPY OF UNROUGHENED NOBLE METAL AND NON-NOBLE METAL FILMS AND TUNNEL JUNCTIONS J C. TSANG, Ph. AVOURIS and J R. KIRTLEY IBM Thomas J Watson Research Center Yorktown Heights, New York, 10598 ABSTRACT We demonstrate that multichannel optical detectors provide the capability of observing Raman Scattering from molecular monolayers in solid-air and solid-solid interfaces in the absence of the conditions considered essential for surface enhanced Raman scattering. We present spectra of adsorbates on smooth Ag films, air- oxrdrzed smooth Al films and Al gratings. Finally, we demonstrate a new configura- tion for surface enhanced Raman scattering which need not involve noble metals. Raman scattering from a doped Al/AlOx/Sn tunnel junction provides a specific example of such a configuration. INTRODUCTION Surface infrared and Raman spectroscopies have several potential advantages over vibrational electron spectroscopies, advantages which are associated with the higher spectral resolutron, the absence of UHV requirements and the ability to probe interfaces However, the lower sensitivity of Raman scattering has prevented its wide application to surface studies. In recent years significant attention has been focused on surface enhanced Raman scattering (SERS) from molecules adsorbed on rough noble metal surfaces.(‘) Under these conditions the Raman cross-section is strongly enhanced (up to lo6 x) and the scattering can be detected by conventional techniques.(*) Unfortunately, SERS is essentially restricted to rough noble and alkali metal substrates Recently, however, Campion et a1.(2) have shown that by using multichannel optical detectors they could detect the Raman spectrum of a molecular monolayer on a polished Ni surface in- UHV. In this work, we use multichannel Raman spectroscoPY WW to study 0368-2048/83/0000-0000/$03.00 0 1983 Ekevier Sclentlfic Pubhahii Company