Contents lists available at ScienceDirect Nuclear Inst. and Methods in Physics Research B journal homepage: www.elsevier.com/locate/nimb Structural properties of nano-porous GaSb prepared by swift heavy-ion irradiation C. Notthoff a, ⁎ , P. Mota-Santiago a , A. Hadley a , U.H. Hossain a , S. Jordan a , C. Glover b , S. Mudie b , P. Kluth a a Research School of Physics and Engineering, Australian National University, Canberra ACT 2601, Australia b Australian Synchrotron, Melbourne, Australia ARTICLE INFO Keywords: Swift heavy ion SAXS WAXS EXAFS FTIR Raman GaSb Semiconductor Nano-pores ABSTRACT We are investigating the structural and optical properties of nano-porous GaSb formed by swift heavy ion ir- radiation using a combination of high resolution structural characterization techniques including synchrotron based small- and wide-angle X-ray scattering (SAXS/WAXS) and extended X-ray absorption fine structure (EXAFS), as well as optical measurements like Raman and Fourier transform infrared spectroscopy. In contrast to nano-porous GaSb prepared by low energy ion irradiation, the swift heavy ion irradiated samples do not show any sign of homo-polar bonding typical for amorphous materials in EXAFS measurements despite the observed significant structural disorder. Furthermore, X-ray diffraction and Raman-spectroscopy reveal the presence of small (< 10 nm) crystallites inside the pore walls. 1. Introduction GaSb is a narrow band gap semiconductor used in many optoelec- tronic devices such as light emitting diodes, photodetectors, and diode lasers [1,2]. We have recently discovered the evolution of fascinating nano-porous structures in GaSb following swift heavy ion irradiation [3]. Porous semiconductors differ significantly in their physical and chemical properties from their bulk counterparts, due to their micro- structure that is often characterised by a large surface to volume ratio and small feature sizes. Porous silicon, for example, shows an intense, spectrally tuneable luminescence while no optical activity is observed for bulk silicon. The controlled fabrication of porous semiconductors thus paves the way for the development of new materials with appli- cation-specific properties. We have been investigating the structural and optical properties of nano-porous GaSb formed by swift heavy ion irradiation using a com- bination of high resolution structural characterization techniques in- cluding synchrotron based small- and wide-angle X-ray scattering (SAXS/WAXS), extended X-ray absorption fine structure spectroscopy (EXAFS), as well as Raman and Fourier transformation infrared (FTIR) spectroscopy. 2. Experimental GaSb films with a thickness of 2 μm, grown on InP substrates by Metal Organic Chemical Vapour Deposition (MOCVD) were irradiated with 185 MeV 179 Au +13 ions with fluences ranging from 1.2 × 10 12 cm -2 to 1.2 × 10 14 cm -2 at the ANU Heavy Ion Accelerator Facility. All samples were irradiated under vacuum at room tempera- ture and with the ion beam parallel to the surface normal. No further preparation is needed for SAXS/WAXS, Raman and FTIR spectroscopy, which were performed on the samples prior to cleaving for cross-sec- tional SEM imaging. Raman-spectra were taken at room temperature with 532 nm excitation wavelength, 0.03 mW excitation Power and an X50 objective, using a confocal Raman microscope in backscattering geometry (inVia, Renishaw). FTIR-measurements were performed at room temperature and ambient air with a HYPERION-2000 FTIR-mi- croscope in transmission mode attached to a vertex80v FTIR-spectro- meter (Bruker company) using a globar light source, a KBr - beam splitter and an MCT detector. SAXS and WAXS measurements were performed at the SAXS/WAXS-beam line at the Australian Synchrotron. The small angle X-ray scattering data were collected with a Pilatus 1 M detector in grazing incidence geometry with a 7 keV X-ray beam in- clined by 0.1° relative to the sample surface and 943 mm sample-to- detector distance. The SAXS/WAXS-beam line is equipped with a Pilatus 200 K detector attached to a rotatable detector arm allowing for http://dx.doi.org/10.1016/j.nimb.2017.10.015 Received 20 July 2017; Received in revised form 15 October 2017; Accepted 16 October 2017 ⁎ Corresponding author. E-mail address: christian.notthoff@anu.edu.au (C. Notthoff). Nuclear Inst. and Methods in Physics Research B xxx (xxxx) xxx–xxx 0168-583X/ © 2017 Elsevier B.V. All rights reserved. Please cite this article as: Notthoff, C., Nuclear Inst. and Methods in Physics Research B (2017), http://dx.doi.org/10.1016/j.nimb.2017.10.015