Infrared spectroscopy of C–D vibrational modes on diamond (100) surfaces

Abstract

A high resolution analysis of C–D vibrational modes on single crystal diamond using Fourier transform infrared spectroscopy is reported. This method has the advantage over high resolution electron energy loss spectroscopy of a far superior resolution (<1 cm −1 versus ∼10 cm −1). The inherently low surface sensitivity of the former method was overcome by measuring the IR absorption in the attenuated total reflection mode employing a Ge prism. The use of deuterium instead of hydrogen avoids the interference from airborne hydrocarbon contamination. We present data on the diamond (100) surface that was deuterated in a microwave plasma and subjected to a series of isothermal annealing treatments at 700°C. The C–D stretching mode at 2181 cm −1 and the bending mode at 1054 cm −1 could be followed down to a tenth of a monolayer coverage. From the intensity ratio of these bands measured in s- and p-polarization the essentially perpendicular disposition of the C–D bonds has been inferred.