The effects of sub-monolayer laser etching on the chemical and electrical properties of the (100) diamond surface

Tailoring the surface chemistry of diamond is critical to a range of applications from quantum science to electronics. It has been recently shown that dosing the diamond surface with pulsed UV light at fluences below the ablation threshold provides a practical method for precision etching of the surface. Here, we track the evolution of the surface chemistry and its electrical properties as a function of dose using x-ray surface analysis, Hall and resistance measurements. It is found that the surface properties evolve rapidly, even for doses that correspond to removal of less than 5% of the top carbon monolayer and fluences less than 1 J/cm2. As well altering XPS-measured surface populations, sub-monolayer etch doses lower the valence band by up to 0.2 eV, and produce a permanent increase in the conductivity of the hydrogen terminated surface by up to 7 times. Similar enhancements in conductivity are obtained for doses that remove up to 1600 ML. The results provide guidance for manipulating diamond surface chemistry by UV laser etching and introduce a promising method for enhancing the performance of diamond devices such as field-effect transistors. [Display omitted] •Sub-monolayer etch doses of UV alter the top layer chemistry and surface electrical properties.•UV laser doses increase the surface conductivity by 5-7 times.•The UV effect may include rearrangement of the surface to align step edges or make in more {111}-like.