Effet de l’oxygène sur les radiations optiques émises lors de la pulvérisation de l’aluminium par un faisceau d’ions

La présence de l’oxygène au voisinage d’une surface métallique lors d’unbombardement ionique, provoque une décroissance du rendement totalde pulvérisation mais elle modifie considérablement les proportions desdiverses espèces éjectées de cette surface. Dans ce travail, nous noussommes intéressés à l’effet de l’oxygène sur la lumière émise lors de lapulvérisation d’une surface d’aluminium par des ions Kr+ d’énergiecinétique de 5 keV. Le spectre de luminescence relevé à une pression de10-7 Torr est comparé à celui mesuré lorsque la cible est soumise à uneatmosphère d’oxygène. L’examen des intensités des raies spectralesmontre que toutes les raies Al I manifestent une dépendance positiveavec la pression en oxygène alors que des raies Al II manifestent unedépendance négative. Nous avons aussi enregistré que des raies Al IIIrestent insensibles à la présence de ce gaz. Ces observations sontcomparées avec les spectres de luminescences de l’alumine bombardéedans les mêmes conditions expérimentales. Les résultats obtenus sontinterprétés dans le cadre du modèle de transfert d’électrons entre lasurface et la particule éjectée. La validité du modèle suggère qu'en présence de l'oxygène, une structure est formée et dont le schéma debandes d'énergie est intermédiaire entre celui de l'aluminium et celui del'alumine.Mots-clés : pulvérisation, émission optique, aluminium, alumine, modèlede transfert d’électrons; analyse de surface, spectroscopie optique

Effects of lithium insertion into vanadium pentoxide thin films. Continuum radiation study

Optical emission of Lix(x=0.2,0.7,1.2)V2O5 has been studied during 5 keV Kr+ ions bombardment. Continuous luminescence was observed in a broad wavelength range between 280 and 340 nm. Generally, the emission intensity was influenced by the quantities of lithium giving rise to transient effects as well as an increase in the line intensity. The experimental results suggest that the continuum emission depends on the nature of surface interaction between lithium and vanadium pentoxide and is very probably related to its electronic structure

Angular distribution of sputtered alloy. Experimental and simulated study

Angular distribution of Cu and Be atoms sputtered from Cu98 Be2 alloy under 5 Kr+ ion bombardment were measured at different angle of incidences (0, 30, 70 and 80○). The sputtered material is collected on a MylarTM foil surrounding the target. The used collector was mounted at different ejection angles and analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The SRIM-code program was employed to obtain the sputtering yield of Cu and Be from simulated Cu98 Be2 target. The experiment was combined with simulations and revealed that both of them were in a fairly good agreement. Furthermore, angular distribution of differential sputtering yields of both Cu and Be showed over-cosine tendency

Ion Beam Sputtering Monitored by Optical Spectroscopy

Optical spectroscopy gives a simple means to follow the evolution of the surface composition during ion beam sputtering. This is illustrated by three examples: air oxidised metals (Al and Cu), various CuAl alloys and the $Cu_{98}Be_2$ alloy. Several time scales are distinguished, corresponding to different processes: the elimination of surface contaminants, the removal of the corroded layer. The implications for the use of ion beam optical spectroscopy in surface analysis are discussed

On the validity of the electron transfer model in photon emission from ion bombarded vanadium surfaces

The spectral structure of the radiation (250–500 nm) emitted during sputtering of clean and oxygen-covered polycrystalline vanadium and V2O5 by 5 keV Kr+ ions is presented. The optical spectra obtained by bombarding the vanadium target consist of series of sharp lines, which are attributed to neutral and ionic excited V. The same lines are observed in the spectra of V2O5 and vanadium when oxygen is present. The absolute intensities of VI and VII lines are measured under similar conditions for all spectra. The difference in photon yield from the clean and oxide vanadium targets is discussed in terms of the electron-transfer processes between the excited sputtered and electronic levels of the two types of surfaces. We have examined the existing models of ionisation, excitation, neutralisation and de-excitation of atomic particles in the vicinity of solid surfaces. Continuum radiation was also observed and interpreted as a result of the emission of excited molecules of the metal-oxide