Indra Sulania, Dinesh Agarwal, Manish Kumar, Mushahid Husain and D. K. Avasthi
1Inter University Accelerator Centre, New Delhi 110067, India
2Jamia Millia Islamia, New Delhi 110025, India
Adv. Mater. Lett., 2013, Ion Beam Special Issue, 4 (6), pp 402-407
Publication Date (Web): Mar 16, 2013
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We present the formation of Ge nanostructures by bombardment of 1.5 keV Ar atoms on Ge (100). The bombardment was carried out at normal incidence with variation in the fluences from 5x1015 to 3x1017 atoms/cm2. Near surface chemical study on the pristine and irradiated Ge samples has been carried out using X-ray Photoelectron Spectroscopy. In the near surface region of pristine sample, prominence of Ge4+ was observed by 3d core level present at a binding energy of 33.5 eV. After the irradiation, the evolution of two new core level peaks at binding energies of 29.8 and 30.4 eV confirms the reduction of Ge4+ to elemental Ge. Atomic Force Micrographs show an increase in surface roughness from 0.4 nm to 10 nm for pristine to sample irradiated at highest fluence. Using the scaling laws and calculating the roughness and growth exponents deduced from Power Spectral Density analysis, it has been found that ion induced coarsening leads to the surface roughening. Further, using the simulation code, it is found that with increasing fluence of bombardment, the deformation of surface starts initially which later on results in simultaneous formation of dots and pits.
Germanium, Ion Bombardment, Atomic Force Microscopy, X-ray Photoelectron Spectroscopy.