Valence-band photoemission of the H-plasma annealed (100) textured CVD diamond surface

A (100) textured chemical vapor deposited (CVD) diamond thin film was exposed to a hydrogen plasma at 850°C as a cleaning procedure and was subsequently investigated by X-ray absorption spectroscopy (XAS) and ultraviolet photoelectron spectroscopy (UPS) with synchrotron radiation in the range 30 eV < hv < 150 eV. The dominant feature of the UPS spectra between 30 and 60 eV excitation energy is the presence of a distinct peak at around 1.8 eV below the Fermi level. This feature can be identified as a surface state of the reconstructed diamond (100) surface. In analogy to reported UPS measurements of reconstructed natural diamonds of (100) orientation reported earlier, the results are discussed in terms of a surface reconstruction of the (100) textured CVD diamond film. The electronic properties of the (100) textured CVD diamond thin film are compared to the ones of annealed or H-plasma exposed natural diamond (100). The UPS measurements of a hydrogen-plasma exposed, reconstructed (100) textured CVD diamond surface discussed here are, to our knowledge, the first reported