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The luminescence of during and irradiation was measured in the 190 - 820 nm wavelength range. The luminescence evolution with the ion fluence exhibits two behaviours : (i) at low fluence, the amount of centres increases; (ii) at high fluences, these defects are completely (F centres) or partially ( centres) annihilated. This phenomenon results from two concomittant mechanisms : a conversion between F and defects and a destruction of both luminescent species resulting from the radiation-induced damage. By using a simple model we have determined the cross sections associated with creation and annihilation of the centres. The irradiated samples were also investigated by cathodoluminescence and Auger electron spectroscopy. A higher concentration of structural defects and centres is evidenced at the sample area previously irradiated by ions, leading to an unsteady regime of the surface potential under electron excitation.

Auger electron spectroscopy (AES) and electron loss spectroscopy (ELS) have been performed in order to investigate a (100) InP surface subjected to argon ion bombardment at low energy. It has been found that preferential sputtering of phosphorus-impurities species during the cleaning stage results in the formation of a I~.51Po.43 disordered layer. Within the sampling depth of the In MNN Auger electrons, about 114 of the total In atoms are of metallic type. Our experimental results are not consistent with the formation of pure In islands over a stoichiometric InP surface. If In clusters are present in the disordered surface, they are associated with adsorbed phosphorus. Prolonged ion bombardment increases the surface roughness as detected by ELS and scanning electron microscopy (SEM). INTRODUCTION EXPERIMENTALMuch work has been done in the last few years on the evolution of InP surfacer; with argon ion bombardment and annealing in UHV'-6. Depletion of phosphorus, formation of metallic indium and change of the specimen topography are iisually reported. Phosphorus enrichment of the surface layer may sometimes be owing to a complex behaviour involving diffusion from the bulk, surface segregation and desorption. However, some points are still controversial; they are related to the characterization of the InP surface structure, the detection of indium clustering, and the interpretation of Auger electron and electron loss spectra with combined topographical and chemical effects. Furthermore, the influence of the incident electron beam in Auger electron spectroscopy (AES), electron loss spectroscopy (ELS), electron diffraction and microscopy experiments on InP must be carefully checked; electronstimulated oxidation' and charging effects are detected at oxygen pressure and primary current density as low asThe present article reports upon a detailed examination of the evolution of InP (100) surface with Ar-ion bombardment; new AES and ELS data are provided using a high resolution electron spectrometer, direct N ( E ) mode of recording the spectra and normalization of the Auger signal by the background. This normalization procedure excludes to a large extent the instrumental parameter~ll-'~ and, of course, the possible spurious features due to the differentiation techniques. It is useful to compare related data derived from different apparatuses. Furthermore, the Auger peak to background ratio ( P / B ) minimizes the effects of surface roughness; these are rather studied using the evolution of the surface and voliime plasmon losses.Torr and lop3 A cm-2 respectively." AES and ELS measurements were performed with a hemispherical ana1y~er.I~ A constant pass energy E, = 80eV inside the deflectors was used to give a good compromise between resolution and transmission. The surface was excited by a 6 = 20" grazing incidence electron beam of E = 1850 eV energy with a low current be changed for special investigations. An ion pump associated with a cooled titanium sublimator assured a base pressure of lo-' Torr.The samples were (100)...