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 degrees C as a cleaning procedure and was subsequently investigated by X-ray absorption spectroscopy (XA S) and ultraviolet photoelectron spectroscopy (UPS) with synchrotron r adiation 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 na tural diamonds of (100) orientation reported earlier, the results are discussed in terms of a surface reconstruction of the (100) textured C VD diamond film. The electronic properties of the (100) textured CVD d iamond thin film are compared to the ones of annealed or H-plasma expo sed natural diamond (100). The UPS measurements of a hydrogen-plasma e xposed, reconstructed (100) textured CVD diamond surface discussed her e are, to our knowledge, the first reported.