Influence of the local environment on Mn acceptors in GaAs

Author： Benjamin Anne Gupta Jay A Lee Donghun Gohlke David

E-ISSN： 1361-648X|27|15|154202-154209

ISSN： 0953-8984

Source： Journal of Physics: Condensed Matter, Vol.27, Iss.15, 2015-04, pp. : 154202-154209

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Abstract

As transistors continue to shrink toward nanoscale dimensions, their characteristics are increasingly dependent on the statistical variations of impurities in the semiconductor material. The scanning tunneling microscope (STM) can be used to not only study prototype devices with atomically precise placement of impurity atoms, but can also probe how the properties of these impurities depend on the local environment. Tunneling spectroscopy of Mn acceptors in GaAs indicates that surface-layer Mn act as a deep acceptor, with a hole binding energy that can be tuned by positioning charged defects nearby. Band bending induced by the tip or by these defects can also tune the ionization state of the acceptor complex, evident as a ring-like contrast in STM images. The interplay of these effects is explored over a wide range of defect distances, and understood using iterative simulations of tip-induced band bending.