Reversible control of the electronic density of states at the Fermi level of Ca3Co4O9+δ misfit-layered oxide single crystals through O+/H+ plasma exposure
Misfit-layered Ca3Co4O9 crystals were grown and characterized via XRD, SEM, and photo-emission spectroscopy (PES). The evolution of the intensity at the Fermi level (E F) with varying oxygen content was studied by PES. Oxygen species were successfully introduced and removed through O+ and H+ microwave-plasma (2.45GHz, 2-5mbar) treatments, respectively. A 5min O+ plasma exposure was observed to result into a drastic enhancement in the E F intensity, demonstrating the influence of oxygen content to the charge carrier population in layered cobalt-oxide material
