Dresden 2009 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 18: Impurities/amorphous semiconductors
HL 18.3: Talk
Tuesday, March 24, 2009, 12:30–12:45, POT 151
Structural modification of swift heavy ion irradiated amorphous Ge layers — •Werner Wesch1, Claudia S. Schnohr2, Patrick Kluth2, Zohair S. Hussain2, Leandro L. Araujo2, R. Giulian2, David J. Sprouster2, Aydan P. Byrne2, and Mark C. Ridgway2 — 1Institute of Solid State Physics, Friedrich Schiller University Jena — 2Department of Electronic Materials Engineering, Australian National University, Canberra
To study the effect of high electronic energy deposition on amorphous Ge layers, crystalline Ge wafers were amorphised to a thickness of 3.2μm by multiple Ge ion implantation at 80 K. A Au grid was then evaporated on the sample surface which was partly masked during the irradiation. The samples were then irradiated with various fluences of 185 MeV Au ions at room temperature and an angle of incidence of 45° with respect to the surface normal. The irradiated samples were analysed by optical microscopy, surface profilometry and scanning electron microscopy (SEM). Subsequent to irradiation, a change in sample surface colour from light brown to black with increasing ion fluence was readily apparent. The change of colour was accompanied with swelling of the amorphous layer, the latter also increasing with ion fluence. The swelling was a consequence of void formation within the amorphous layer, which transformed into a sponge-like porous structure at higher ion fluences. Additionally, as in a-Si, a surface shift in the irradiated region along the projection of the ion beam to the sample surface increasing with the ion fluence was observed demonstrating liquid polymorphism is common to these two semiconductors.