Surface characterization of oxide growth on porous germanium films oxidized in air

► We study as-deposited and chlorinated porous Ge films oxidized in air. ► X-ray photoelectron spectroscopy was used to characterize oxide phases. ► A GeOx transition layer grows with logarithmic rate kinetics. ► The transition layer oxide phases cease growing once chlorine is removed. ► We observe continual growth of GeO2 on the transition layer with time.