1. Depth Resolved Scanning Tunneling Spectroscopy of Shallow Acceptors in Gallium Arsenide
- Author
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Stefan Malzer, Rainer G. Ulbrich, Sebastian Loth, Gottfried H. Döhler, Martin Wenderoth, and L. Winking
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Scanning tunneling spectroscopy ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,Heterojunction ,Electronic structure ,Conductivity ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Molecular physics ,law.invention ,Gallium arsenide ,Crystal ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,chemistry ,law ,Condensed Matter::Superconductivity ,Scanning tunneling microscope ,Anisotropy - Abstract
Scanning tunneling spectroscopy (STS) at 8 K is used to study single shallow acceptors embedded near {110}-surfaces in gallium arsenide (GaAs). At appropriate bias voltages the circularly symmetric contrast normally observed for charged defects evolves into a pronounced triangular shaped protrusion. Comparing dopants at different depths under the surface, we find a linear shift of the associated conductivity maximum along directions. Comparative studies of Carbon and Zinc acceptors in a modulation-doped heterostructure reveal that both dopants act similarly. The experimental findings suggest that the highly anisotropic features induced by acceptors resemble a bulk property of the GaAs crystal prominently demonstrating its Zincblende symmetry.
- Published
- 2006
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