Influence of electronic energy deposition on the structural modification of swift heavy-ion-irradiated amorphous germanium layers

Journal Article · Tue Feb 01 00:00:00 EST 2011 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.83.054113· OSTI ID:21538108

Steinbach, T; Schnohr, C S; Wesch, W ^[1]; Kluth, P; Giulian, R; Araujo, L L; Sprouster, D J; Ridgway, M C ^[2]

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1. Institut fuer Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)
2. Australian National University, Research School of Physics and Engineering, Canberra ACT 0200 (Australia)

Swift heavy-ion (SHI) irradiation of amorphous germanium (a-Ge) layers leads to a strong volume expansion accompanied by a nonsaturating irreversible plastic deformation (ion hammering), which are consequences of the high local electronic energy deposition within the region of the a-Ge layer. We present a detailed study of the influence of SHI irradiation parameters on the effect of plastic deformation and structural modification. Specially prepared a-Ge layers were irradiated using two SHI energies and different angles of incidence, thus resulting in a variation of the electronic energy deposition per depth {epsilon}{sub e} between 14.0 and 38.6 keV nm{sup -1}. For all irradiation parameters used a strong swelling of the irradiated material was observed, which is caused by the formation and growth of randomly distributed voids, leading to a gradual transformation of the amorphous layer into a sponge-like porous structure as established by cross-section scanning electron microscopy investigations. The swelling depends linearly on the ion fluence and on the value of {epsilon}{sub e}, thus clearly demonstrating that the structural changes are determined solely by the electronic energy deposited within the amorphous layer. Plastic deformation shows a superlinear dependence on the ion fluence due to the simultaneous volume expansion. This influence of structural modification on plastic deformation is described by a simple approach, thus allowing estimation of the deformation yield. With these results the threshold values of the electronic energy deposition for the onset of both structural modification and plastic deformation due to SHI irradiation are determined. Furthermore, based on these results, the longstanding question concerning the reason for the structural modification observed in SHI-irradiated crystalline Ge is answered.

• OSTI ID: 21538108
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 5; Other Information: DOI: 10.1103/PhysRevB.83.054113; (c) 2011 American Institute of Physics; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
CROSS SECTIONS
DEFORMATION
EXPANSION
GERMANIUM
HEAVY IONS
INCIDENCE ANGLE
ION BEAMS
IRRADIATION
KEV RANGE 10-100
LAYERS
MODIFICATIONS
PHYSICAL RADIATION EFFECTS
PLASTICITY
POROUS MATERIALS
SCANNING ELECTRON MICROSCOPY
SWELLING
TRANSFORMATIONS
VARIATIONS
BEAMS
CHARGED PARTICLES
ELECTRON MICROSCOPY
ELEMENTS
ENERGY RANGE
IONS
KEV RANGE
MATERIALS
MECHANICAL PROPERTIES
METALS
MICROSCOPY
RADIATION EFFECTS