Local charge trapping in Ge nanoclustersdetected by Kelvin probe force microscopy

The understanding of local charge trapping on the nanoscale is crucial for the design of novel electronic devices and photodetectors based on SiGe nanoclusters (NCs). Here, the local spatial distribution of the surface potential of the Ge NCs was detected using Kelvin probe force microscopy (KPFM)....

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Bibliographic Details
Published in:Applied surface science 2016-12, Vol.389, p.783-789
Main Authors: Kondratenko, S.V., Lysenko, V.S., Kozyrev, Yu. N., Kratzer, M., Storozhuk, D.P., Iliash, S.A., Czibula, C., Teichert, C.
Format: Article
Language:English
Subjects:
Carrier lifetime
Heterostructures
Quantum dots
Recombination processes
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Summary:The understanding of local charge trapping on the nanoscale is crucial for the design of novel electronic devices and photodetectors based on SiGe nanoclusters (NCs). Here, the local spatial distribution of the surface potential of the Ge NCs was detected using Kelvin probe force microscopy (KPFM). Different surface potentials between Ge NCs and the wetting layer (WL) surface were detected at room temperature. Changes of the local contact potential differences (CPD) were studied after injection of electrons or holes into single Ge NCs on top of the Si layer using a conductive atomic force microscopy tip. The CPD image contrast was increased after electron injection by applying a forward bias to the n-tip/i-Ge NC/p-Si junction. Injecting holes into a single Ge NC was also accompanied by filling of two-dimensional states in the surrounding region, which is governed by leakage currents through WL or surface states and Coulomb charging effects. A long retention time of holes trapped by the Ge NC was found.
ISSN:0169-4332
1873-5584
DOI:10.1016/j.apsusc.2016.07.148