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 × 1017 ions/cm2. 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.

/pdf/investigations-of-ripple-pattern-formation-on-germanium-3wx5lqrkl1.pdf

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

Background: Germanium (Ge) nanostructures exhibit wide range of potential applicationsin the field of nanoscale devices due to their excellent optical and electrical properties and have gainedsignificant interest due to the Bohr exciton radius. Bohr radius of Ge (24.3 nm) is larger than that of Si(4.9 nm), leading to quantum size effects and nanostructures with controllable bandgaps.Methods: This article provides a comprehensive review on various electrolytes for electrodeposition procedures developedto obtain the Ge nanostructures of desired structure, diameter, and density. We discuss the growth mechanisms andinfluence of different parameters such as type of solution, concentration, and value of applied potential or current density.Results: The ionic liquids can be used for the development of Ge nanostructures and provide extensive electrochemicalwindows for electrodeposition. The obtained Si x Ge 1-x structures also exhibited strong color change (from red to blue) atroom temperature during the electrodeposition, which is likely to be due to a quantum size effect.Conclusion: The main advantages of the ionic liquids are ‘it does not decompose’, easy to purify and dry. Moreover, itexhibits fairly extensive electrochemical windows greater than 5 V for electrodeposition. Electrodeposition of Si x Ge 1–x nanostructures from ionic liquids is quite a favorable process. The 3DOM Ge electrode is a promising material for nextgenerationlithium ion battery because of its high irreversible specific capacity. Few relevant patents to the topic havebeen reviewed and cited.

Electrodeposited Ge Nanostructures Prepared by Different Non-Aqueous Solutions and their Application in Lithium Ion Battery: A Review.

Lithography is the most crucial step in the semiconductor microfabrication workflow. Continuous features size shrinking co-occurs with the reduction of the exposure wavelength: a move from 193 nm l ...

Offline study of next generation EUV pellicle materials and performances : From experimental design to material characterization

The characteristics of zinc oxide (ZnO) films with different thicknesses grown on graphene, i.e., single-layer graphene (SLG) and multilayer graphene (MLG), on insulators at 500 °C using a reaction between dimethylzinc and high-temperature water generated by a catalytic reaction on Pt nanoparticles were investigated. The growth rate of continuous ZnO layer on MLG was higher than that of SLG. XRD patterns for the ZnO films exhibited an intense diffraction peak associated with (0002) plane and small ones associated with (10–10) and (10–11) planes, suggesting the grown hexagonal wurtzite ZnO is not perfectly along c-axis direction due to the nature of the used graphene structures. The FWHM values of the 2θ for ZnO (0002) were < 0.20° and 0.16° for ZnO on SLG and MLG, respectively. The photoluminescence at room temperature exhibited strong emission peak at 3.28 eV with no significant level of green emission indicating negligible defect density in the grown ZnO films. The results suggest that accurate optical bandgap cannot be determined from the transmittance spectra for the ZnO films with thickness and roughness higher than 1 µm and 20 nm, respectively. The results also suggest that the thickness of ZnO films should be below 1 µm in order to obtain acceptable level of transmittance in visible up to near infrared region.

CVD growth of zinc oxide thin films on graphene on insulator using a high-temperature platinum-catalyzed water beam

Formation of germanium (111) on graphene on insulator by rapid melting growth for novel germanium-on-insulator structure

The effects of annealing temperatures on composition and strain in SixGe1-x, obtained by rapid melting growth of electrodeposited Ge on Si (100) substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100 °C for 1 s. All annealed samples show single crystalline structure in (100) orientation. A significant appearance of Si-Ge vibration mode peak at ~400 cm-1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of SixGe1-x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.

https://www.mdpi.com/1996-1944/7/2/1409/pdf?view=inline

Tahsin Morshed

Papers

The Effects of Annealing Temperatures on Composition and Strain in SixGe1-x Obtained by Melting Growth of Electrodeposited Ge on Si (100).

Formation of germanium (111) on graphene on insulator by rapid melting growth for novel germanium-on-insulator structure

Formation of large-grain crystalline germanium on single layer graphene on insulator by rapid melting growth