کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10672451 1009859 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Characterization of ion-irradiation-induced nanodot structures on InP surfaces by atom probe tomography
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد فناوری نانو (نانو تکنولوژی)
پیش نمایش صفحه اول مقاله
Characterization of ion-irradiation-induced nanodot structures on InP surfaces by atom probe tomography
چکیده انگلیسی
Surfaces of InP were bombarded by 1.9 keV Ar+ ions under normal incidence. The total accumulated ion fluence the samples were exposed to was varied from 1×1017 cm−2 to 3×1018 cm−2 and ion flux densities f of (0.4−2)×1014 cm−2 s−1 were used. Nanodot structures were found to evolve on the surface from these ion irradiations, their dimensions however, depend on the specific bombardment conditions. The resulting surface morphology was examined by atomic force microscopy (AFM). As a function of ion fluence, the mean radius, height, and spacing of the dots can be fitted by power-law dependences. In order to determine possible local compositional changes in these nanostructures induced by ion impact, selected samples were prepared for atom probe tomography (APT). The results indicate that by APT the composition of individual InP nanodots evolving under ion bombardment could be examined with atomic spatial resolution. At the InP surface, the values of the In/P concentration ratio are distinctly higher over a distance of ~1 nm and amount to 1.3-1.8. However, several aspects critical for the analyses were identified: (i) because of the small dimensions of these nanostructures a successful tip preparation proved very challenging. (ii) The elemental compositions obtained from APT were found to be influenced pronouncedly by the laser pulse energy; typically, low energies result in the correct stoichiometry whereas high ones lead to an inhomogeneous evaporation from the tips and deviations from the nominal composition. (iii) Depending again on the laser energy, a prolific emission of Pn cluster ions was observed, with n≤11.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ultramicroscopy - Volume 159, Part 2, December 2015, Pages 232-239
نویسندگان
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