17th International Conference on Ion Beam Modification of Materials

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HIGH RESOLUTION RADIAL DISTRIBUTION FUNCTION OF AMORPHOUS GERMANIUM BY X-RAY DIFFRACTION OF MEMBRANES MADE BY ION IMPLANTATION

Sjoerd Roorda*, Chris Martin, and Stefan Kycia

poster presentation: Tuesday 2010-08-24 05:00 PM - 07:00 PM in section Defect-induced modification of materials
Last modified: 2010-06-02

Abstract


We have made amorphous germanium membranes of very high purity by self-ion implantation of crystalline germanium and analysed these samples by high energy x-ray diffraction. A five-element energy dispersive detector was used to distinguish elastic and inelastic scattered x-rays and thus obtain a reliable structure factor from 0.1 to 55.5 Å-1. Two samples were measured: one "as-implanted" which received no further treatment and one "relaxed" which had been thermally annealed at 350 °C in order to induce structural relaxation. Comparing the RDFs of these two samples, and comparing those to RDFs measured earlier on similarly prepared a-Si samples [1], reveals the following new information, some expected and some surprising:

 

(1) The coordination number of a-Ge is slightly smaller than that of a-Si

(2) The 2nd peak, measured at high resolution, reveals a fine structure which will require detailed modelling for a full understanding and may it possible to distinguish between the contribution of 2nd and 3rd neighbours to the 2nd peak.

(3) Structural relaxation leads to ordering, measurable in the RDF, beyond 6 Å and thus much beyond the 2nd nearest neighbour.

 

[1] K. Laaziri et al., Phys. Rev. B 60 (1999) 13520.


Author(s) affiliation:
Sjoerd Roorda*, Université de Montréal, Canada
Chris Martin, Guelph University, Canada
Stefan Kycia, Guelph University, Canada

*presenting author
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