Tunable Density-of-States in Chromium Oxide Thin Films via Room Temperature Laser Ablation

Chromium oxide thin films were deposited at room temperature, via reactive laser ablation under varying O₂ pressures and analyzed using in-situ X-ray Photoelectron Spectroscopy. Cr 2p spectra exhibited spin-orbit splitting, with peak separations ranging from 9.2 to 9.5 eV. Cr³⁺, and Cr⁴⁺ states were identified, with 2p_3/2 binding energies between 576.8 and 582.5 eV. Quantitative analysis confirmed that lower O₂ pressures favored Cr₂O₃ growth, while higher pressures promoted CrO₂. Near-Fermi-level spectra revealed significant Density-Of-States modulation, with the Valence Band Maximum shifting from 1.25 to 3.3 eV. A direct correlation between O₂ pressure and electronic structure was established.