Unravelling the free electron behavior in InN

• Precise measurement of the optical Hall effect in InN using magneto-optical generalized ellipsometry at IR and THz wavelengths, allows us to decouple the surface accumulation and bulk electron densities in InN films by non-contact optical means and further to precisely measure the effective mass and mobilities for polarizations parallel and perpendicular to the optical axis. Studies of InN films with different thicknesses, free electron densities and surface orientations enable an intricate picture of InN free electron properties to emerge. Striking findings on the scaling factors of the bulk electron densities with film thickness further supported by transmission electron microscopy point to an additional thickness dependent doping mechanism unrelated to dislocations. Surface electron accumulation is observed to occur not only at polar but also at non-polar and semi-polar wurtzite InN, and zinc blende InN surfaces. The persistent surface electron density shows a complex behavior with bulk density and surface orientation. This behavior might be exploited for tuning the surface charge in InN.

Nyckelord

wide band gap semiconductors | dislocations | electron density | Hall effect | III-V semiconductors | indium compounds | magneto-optical effects | semiconductor doping | semiconductor thin films | surface states | transmission electron microscopy | InN | optical Hall effect | magneto-optical generalized ellipsometry | surface electron accumulation | free electron behavior | films | effective mass | mobilities | surface orientations | scaling factors | transmission electron microscopy | doping | surface electron density | dislocations | surface charge | zinc blende surfaces | InN | Hall effect | Optical polarization | Doping | Effective mass | Optical surface waves | Optical variables measurement | Electron optics

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