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Investigations of ripple pattern formation on Germanium surfaces using 100-keV Ar(+) ions.

Sulania I, Agarwal D, Husain M, Avasthi DK - Nanoscale Res Lett (2015)

Bottom Line: The formation of nanoripples initiates at an angle of θ ~ 45°.Ripple pattern formation has taken place on the Ge surface in the energy regime of 100 keV as compared to the other reports which had been carried out using very low energy ions.Raman spectra reveal that the near surface of crystalline Ge samples becomes amorphous due to interaction of Ar(+) ions due to creation of defects through collision cascades.

View Article: PubMed Central - PubMed

Affiliation: Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110067 India ; Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India.

ABSTRACT
We have investigated the formation of nanoripples on the surface of germanium, Ge(100), due to the effect of 100-keV Ar (+) ion irradiation. The irradiation was carried out at different incidence angles from 0° to 75° in steps of 15° with respect to the surface normal with a fixed ion fluence of approximately 3 × 10(17) ions/cm(2). Atomic force micrographs show an increase in surface roughness from 0.5 to 4.3 nm for the pristine sample and the sample irradiated at 60° incidence angle due to cos(-1)(θ) dependence on sputtering yield. With increase in angle of incidence, there is transition observed from nanodots to aligned nanodots perpendicular to the direction of the beam. There is an increase in size of the nanostructures observed from 44 to 103 nm with angle of incidence. The formation of nanoripples initiates at an angle of θ ~ 45°. Ripple pattern formation has taken place on the Ge surface in the energy regime of 100 keV as compared to the other reports which had been carried out using very low energy ions. Raman spectra reveal that the near surface of crystalline Ge samples becomes amorphous due to interaction of Ar(+) ions due to creation of defects through collision cascades.

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Graph between angle of incidence of ion beam with rms roughness and size of nanodots.
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Fig4: Graph between angle of incidence of ion beam with rms roughness and size of nanodots.

Mentions: The variation in rms roughness and size of dots with angle of incidence of the ion beam is plotted in Figure 4. The size of the dots and rms roughness keep on increasing with the angle of incidence and reaches the maximum value for 60° and again decreases to 0.3 nm for the 75° incidence angle. This happens because as the angle is changing, the ion beam is penetrating in lesser depths and hence the sputtering would be more from the surface of Ge. Therefore, the roughness is found to be maximum for 60°. The nanopatterns appear on the surface of a material due to the interplay of surface diffusion and sputtering due to the impact of energetic ions. This is minimum at 75° incidence angle due to lesser ion interaction with the surface atoms and also a decrease in ion-induced diffusion.Figure 4


Investigations of ripple pattern formation on Germanium surfaces using 100-keV Ar(+) ions.

Sulania I, Agarwal D, Husain M, Avasthi DK - Nanoscale Res Lett (2015)

Graph between angle of incidence of ion beam with rms roughness and size of nanodots.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385137&req=5

Fig4: Graph between angle of incidence of ion beam with rms roughness and size of nanodots.
Mentions: The variation in rms roughness and size of dots with angle of incidence of the ion beam is plotted in Figure 4. The size of the dots and rms roughness keep on increasing with the angle of incidence and reaches the maximum value for 60° and again decreases to 0.3 nm for the 75° incidence angle. This happens because as the angle is changing, the ion beam is penetrating in lesser depths and hence the sputtering would be more from the surface of Ge. Therefore, the roughness is found to be maximum for 60°. The nanopatterns appear on the surface of a material due to the interplay of surface diffusion and sputtering due to the impact of energetic ions. This is minimum at 75° incidence angle due to lesser ion interaction with the surface atoms and also a decrease in ion-induced diffusion.Figure 4

Bottom Line: The formation of nanoripples initiates at an angle of θ ~ 45°.Ripple pattern formation has taken place on the Ge surface in the energy regime of 100 keV as compared to the other reports which had been carried out using very low energy ions.Raman spectra reveal that the near surface of crystalline Ge samples becomes amorphous due to interaction of Ar(+) ions due to creation of defects through collision cascades.

View Article: PubMed Central - PubMed

Affiliation: Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi, 110067 India ; Jamia Millia Islamia, Jamia Nagar, New Delhi, 110025 India.

ABSTRACT
We have investigated the formation of nanoripples on the surface of germanium, Ge(100), due to the effect of 100-keV Ar (+) ion irradiation. The irradiation was carried out at different incidence angles from 0° to 75° in steps of 15° with respect to the surface normal with a fixed ion fluence of approximately 3 × 10(17) ions/cm(2). Atomic force micrographs show an increase in surface roughness from 0.5 to 4.3 nm for the pristine sample and the sample irradiated at 60° incidence angle due to cos(-1)(θ) dependence on sputtering yield. With increase in angle of incidence, there is transition observed from nanodots to aligned nanodots perpendicular to the direction of the beam. There is an increase in size of the nanostructures observed from 44 to 103 nm with angle of incidence. The formation of nanoripples initiates at an angle of θ ~ 45°. Ripple pattern formation has taken place on the Ge surface in the energy regime of 100 keV as compared to the other reports which had been carried out using very low energy ions. Raman spectra reveal that the near surface of crystalline Ge samples becomes amorphous due to interaction of Ar(+) ions due to creation of defects through collision cascades.

No MeSH data available.


Related in: MedlinePlus