Spectral probing of carrier traps in Si–Ge alloy nanocrystals |
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| Authors: | Ngo Ngoc Ha Nguyen Truong Giang Tran Ngoc Khiem Nguyen Duc Dung Tom Gregorkiewicz |
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| Affiliation: | 1. International Training Institute for Materials Science (ITIMS), Hanoi University of Science and Technology (HUST), Hanoi, Vietnam;2. Van der Waals‐Zeeman Institute (WZI), University of Amsterdam (UvA), Amsterdam, The Netherlands;3. Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology (HUST), Hanoi, Vietnam |
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| Abstract: | Photogenerated carriers in Si–Ge alloy nanocrystals (NCs) prepared by co‐sputtering method were investigated by mean of transient induced absorption. The carrier relaxation features multiple components, with three decay life times of τ ≈ 600 fs, 12 ps, and 15 ns, established for Si0.2Ge0.8 alloy NCs of a mean crystal size of 9 nm and standard deviation of 3 nm. Deep carrier traps, identified at the boundary between the NCs and the SiO2 host with the ionization energy of about 1 eV, are characterized by a long‐range Coulombic potential. These are responsible for rapid depletion of free carrier population within a few picoseconds after the excitation, which explains the low emissivity of the investigated materials, and also sheds light on the generally low luminescence of Si/Ge and Ge NCs. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) |
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| Keywords: | Si− Ge alloys nanocrystals transient induced absorption carrier traps |
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