Optical properties of porous Sb-based semiconductors prepared by swift heavy-ion irradiation
Experimental Condensed Matter Physics
Final Report Abstract
Porous semiconductors differ significantly in their physical and chemical properties from their bulk counterparts, governed by their micro-structure. The controlled fabrication of porous semiconductors opens up the possibility to develop new materials and allows an optimization of their application specific properties, e.g. for optoelectronic devices. Swift heavy ions generate fascinating porous structures in Galliumantimonide (GaSb) and Indiumantimonide (InSb). The method is very efficient, easy to control and compatible with current manufacturing processes. It is essential to obtain an in-depth understanding of the influence of swift heavy ion irradiation parameters on the micro-structure as well as the defects produced to control the physical, chemical and micro-structural properties and develop suitable process technologies for the preparation of porous semiconductors. Swift heavy ions generate fascinating porous structures in Galliumantimonide (GaSb) and Indiumantimonide (InSb). The method is very efficient, easy to control and compatible with current manufacturing processes. The applicant has employed a combination of Hall-measurements, Raman spectroscopy, Fourier-Transformation-Infra-Red (FTIR) spectroscopy, scanning electron microscopy (SEM), Rutherford backscattering (RBS), extended X-ray absorption fine structure (EXAFS) analysis, wide-, and small-angle X-ray scattering (WAXS/SAXS) to study swift heavy ion induced porosity in GaSb and InSb. The combination of these techniques allows for a detailed understanding of the interaction of swift heavy ions with crystalline GaSb and InSb, the pore formation process and the influence on the electrical and optical properties. The combination of Raman, EXAFS, RBS, SAXS and WAXS revealed an almost complete amorphisation of the material before significant porosification is observed and surprisingly a radiation induced re-crystallization after the onset of macroscopic porosity. Furthermore, the applicant achieved for the first time measurements of ion tracks in GaSb with SAXS. The results are in good agreement with the RBS measurements, but contradict earlier results published by G. Szenes et al. Further investigation of the energy loss dependence of the track formation is in progress to clarify this discrepancy. FTIR measurements on irradiated samples reveal that nano-porous GaSb turns into a super scatterer, which makes it interesting as an active material in solar and optoelectronic applications. The applicant has also conducted preliminary Hall-measurements on ion irradiated GaSb, showing that nano-porous GaSb might be interesting for thermoelectric applications. The work has provided new and valuable insights into swift heavy ion induced porosity in antimonide semiconductors, initiated a collaboration of the ANU group with Prof. Roland Schmechel from the University Duisburg-Essen and led to a successful funding application in the Discovery Project scheme of the Australian Research Council.
Publications
- (2019) Etched ion tracks in amorphous SiO2 characterized by small angle x-ray scattering: influence of ion energy and etching conditions. Nanotechnology 30 (27) 274001
Hadley, A.; Notthoff, C.; Mota-Santiago, P.; Hossain, U. H.; Kirby, N.; Toimil-Molares, M. E.; Trautmann, C.; Kluth, P.
(See online at https://doi.org/10.1088/1361-6528/ab10c8) - ”Conical etched ion tracks in SiO2 characterised by small angle X-ray scattering”, NIMB 435, 133 (2018)
A. Hadley, C. Notthoff, P. Mota-Santiago, U.H. Hossain, S. Mudie, M.E. Toimil-Molares, C. Trautmann, and P. Kluth
(See online at https://doi.org/10.1016/j.nimb.2017.10.020) - ”Structural properties of nano-porous GaSb prepared by swift heavy-ion irradiation”, NIMB 435, 126 (2018)
C. Notthoff, P. Mota-Santiago, A. Hadley, U.H. Hossain, S. Jordan, C. Glover, S. Mudie, and P. Kluth
(See online at https://doi.org/10.1016/j.nimb.2017.10.015)
