Electron beam induced current and scanning tunnelling spectroscopy correlative study of Cd-xHg_(1-x)Te and CdTe crystals

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Panin, G. N.
Piqueras de Noriega, Javier
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A combined scanning electron microscope-scanning tunnelling microscope (SEM-STM) system has been used to characterize CdxHg1-xTe and CdTe crystals, The electron beam induced current (EBIC) mode of the SEM shows the existence of inhomogeneities in the electronic behaviour of the samples, mainly related to the presence of subgrain boundaries and precipitates. Current imaging tunnelling spectroscopy images and the related normalized differential conductance curves, obtained with the STM, reveal the electronic inhomogeneities at a finer scale. In particular, local variations of the band gap were shown by the conductance curves in regions with strong EBIC contrast. SEM-and STM-based techniques in a combined instrument appear to be complementary characterization techniques.
© 1998 IOP Publishing Ltd. This work was supported by DGICYT (Project PB93-1256) and by CICYT (Project IN93-0012). The help of Professor A M Baró, Dr A Asenjo and Dr J G´omez-Herrero throughout this work is gratefully acknowledged. G N Panin thanks Spanish MEC for a research grant.
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