Compositional and electrical characterisation of the hydrogen-oxygen terminated diamond (100) surface

Abstract

In this work (100) diamond films are hydrogenated using a conventional MWPE-CVD (microwave plasma enhanced chemical vapour deposition) reactor containing a H2 or a H2/O2 mixture. For the latter, XPS (X-ray Photoelectron Spectroscopy) experiments show an increased presence of oxygen at the (sub)-surface. Contrary to pure H2-plasma treated samples, H2/O2-treated layers still posses enough conductivity to enable STS (Scanning Tunneling Spectroscopy) investigations to be carried out after an annealing at 410 °C in UHV (Ultra High Vacuum). Evidence for surface resonance states is detected, yielding a possible explanation for the measured conductivity. UPS (UV Photoelectron Spectroscopy) data point to a negative electron affinity of -0.3 eV for the H2/O2-treated layers.