The free electron behaviour in InN was studied on the basis of decoupled bulk and

surface accumulation electron densities in InN films measured by contactless

optical Hall effect. It was shown that the variation in the bulk electron density with

film thickness did not follow the models of free electrons generated by dislocationassociated

nitrogen vacancies. This finding, further supported by transmission

electron microscopy results, indicated the existence of a different thicknessdependent

doping mechanism. Furthermore, a noticeable dependence of the surface

electron density on the bulk density was observed, which could be exploited for

tuning the surface charge in InN-based devices.

Free Electron Behaviour in InN: on the Role of Dislocations and Surface Electron

Accumulation. V.Darakchieva, T.Hofmann, M.Schubert, B.E.Sernelius,

B.Monemar, P.O.Å.Persson, F.Giuliani, E.Alves, H.Lu, W.J.Schaff: Applied

Physics Letters, 2009, 94[2], 022109