1 research outputs found
Spin-Polarized Electron Transport at Ferromagnet/Semiconductor Schottky Contacts
We theoretically investigate electron spin injection and spin-polarization
sensitive current detection at Schottky contacts between a ferromagnetic metal
and an n-type or p-type semiconductor. We use spin-dependent continuity
equations and transport equations at the drift-diffusion level of
approximation. Spin-polarized electron current and density in the semiconductor
are described for four scenarios corresponding to the injection or the
collection of spin polarized electrons at Schottky contacts to n-type or p-type
semiconductors. The transport properties of the interface are described by a
spin-dependent interface resistance, resulting from an interfacial tunneling
region. The spin-dependent interface resistance is crucial for achieving spin
injection or spin polarization sensitivity in these configurations. We find
that the depletion region resulting from Schottky barrier formation at a
metal/semiconductor interface is detrimental to both spin injection and spin
detection. However, the depletion region can be tailored using a doping density
profile to minimize these deleterious effects. For example, a heavily doped
region near the interface, such as a delta-doped layer, can be used to form a
sharp potential profile through which electrons tunnel to reduce the effective
Schottky energy barrier that determines the magnitude of the depletion region.
The model results indicate that efficient spin-injection and spin-polarization
detection can be achieved in properly designed structures and can serve as a
guide for the structure design.Comment: RevTex