A secondary electron spectroscopy and electron energy loss spectroscopy study of the interaction of oxygen with a polycrystalline aluminum surface

The interaction of oxygen with a polycrystalline aluminum sample has been studied using electron energy loss spectroscopy (ELS) and secondary electron spectroscopy (SES) over a wide range of primary electron energies (30 ⩽ E p ⩽ 250 eV). The use of low primary electron energies enables the detection of interband transitions previously unobserved in reflexion energy loss spectroscopy. For E p > 100 eV, the ELS spectrum is dominated by the plasmon loss structures while for E p below the plasmon excitation threshold only single electron transitions appear. The fine structure in the clean aluminum SES spectrum is attributed to plasmon decay into single electron excitations. For oxygen covered aluminum it may be due to electron scattering on the O 2p and O 2s oxygen induced orbitals.