Abstract
The problem of Fermi-level pinning at semiconductor-metal contacts is readdressed starting from first-principles calculations for Al/GaAs. We give quantitative evidence that the Schottky barrier height is very little affected by any structural distortions on the metal side---including elongations of the metal-semiconductor bond (i.e. interface strain)---whereas it strongly depends on the interface structure on the semiconductor side. A rationale for these findings is given in terms of the interface dipole generated by the ionic effective charges.
Highlights
Despite several decades of extensive experimental and theoretical work, [1] the key factors affecting the Fermilevel pinning at metal-semiconductor contacts have not yet been clearly assessed
We give quantitative evidence that the Schottky barrier height is very little affected by any structural distortions on the metal side—including elongations of the metal-semiconductor bond—whereas it strongly depends on the interface structure on the semiconductor side
Since the microscopic morphology of the interface is not experimentally accessible, the controversy concerns even the very basic issue as to whether the pinning is determined by intrinsic interface states which exist even at an abrupt ideal interface, or by extrinsic electronic states arising from native defects
Summary
Despite several decades of extensive experimental and theoretical work, [1] the key factors affecting the Fermilevel pinning at metal-semiconductor contacts have not yet been clearly assessed. The effects of interface morphology on Schottky barrier heights: a case study on Al/GaAs(001)
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