Investigation of the Stokes to anti‐Stokes ratio for germanium nanowires obtained by electrochemical deposition

Abstract

Germanium nanowires fabricated by the electrochemical liquid–liquid–solid deposition from water solutions on titanium coated silicon substrate were studied by Raman spectroscopy in order to estimate the heating effect of exciting radiation. The Stokes to anti‐Stokes ratio was determined for crystalline Ge wafer and for nanowires with different mean diameters at two different excitation wavelengths. It was demonstrated that local heating by exciting laser radiation can lead to an increase in temperature sufficiently high for crystallization of initially amorphous Ge nanowires. The results presented may be of great use for fabricating devices, such as metal ion batteries or thermoelectric elements, based on Ge nanowire.

Heat Treatment Effect on Structural and Optical Properties of Germanium Nanowires Obtained by Electrochemical Deposition

“…Previously, the effect of local laser crystallization of unannealed Ge NW under the action of an exciting laser was demonstrated. [ 16,17 ] To obtain the parameter y , which was necessary for calculating the volume fraction, the size of the nanocrystals was estimated by the method described in the Experimental Section. The nanocrystal size for sample 3 was found to be around 3–4 nm at the beginning of Raman measurements and increased up to 5 nm at the end.…”

“…Indium nanoparticles were deposited on a Ti foil, as described in previous works. [ 16,17 ] A platinum ring was used as a counter electrode, a standard silver chloride electrode (Mettler‐Toledo InLab Reference Flow) was used as the reference one. The solution contained 0.05 m of germanium (IV) oxide GeO 2 , 0.5 m of potassium sulfate K 2 SO 4 , and 0.5 m of succinic acid.…”

“…[ 12–15 ] Along with this, in our recent studies of such Ge NW by Raman spectroscopy, irreversible changes in the spectral line shape were demonstrated, indicating a structural transformation due to intense exciting radiation. [ 16,17 ] This structural change can be associated with strong heating of Ge NW due to their low thermal conductivity. Heat treatment can change and stabilize the structures under investigation.…”

Effect of some physical perturbations and their interplay on Raman spectral line shapes in silicon: A brief review

“…In the above discussion, Si has been taken as an example because it is one of the well‐known and thoroughly studied materials. Asymmetric Raman line shapes have also been observed from other semiconductors NSs like Germanium [ 44,119–122 ] and polar semiconductors [ 123 ] involving GaAs [ 41 ] and InP and various materials like selenium, cadmium sulfide, zinc oxide, thorium oxide, and nanodiamond [ 124 ] and titanium oxide. [ 38 ] Analyses have been done in order to understand the perturbation in vibrational properties due to the effect of quantum confinement.…”

Laser‐induced heating of porous Ge layers implanted with Ag+ and Cu+ ions

“…Optical excitation of bulk materials rarely leads to their significant heating, but nanostructured materials can be locally heated up to hundreds of degrees due to the action of exciting laser radiation. [1][2][3][4][5] Raman spectroscopy was widely used as a structural method for estimating the size parameters of semiconductor nanostructures. The peak associated with nanostructures is usually shifted towards lower wavenumbers due to the quantum confinement effect, [6][7][8] and it is possible to calculate the average diameter of their nanoelements.…”