Carrier transport characteristics in hexagonal InN thin films

The dark current characteristics of hexagonal InN thin films grown by rf magnetron sputtering on semi-insulating GaAs (111) substrates have been investigated systematically at different temperatures from 10 K to room temperature. The carrier transport characteristics of the InN thin films have been explained successfully on the basis of a grain-boundary barrier model, where the accumulation of holes at the grain boundaries has been found to play a key role. From the yielded height of the grain-boundary barrier, we can estimate the trap concentration in the InN thin films, which are in agreement with the micro-Raman results. The results give clear evidence that the grain-boundary barrier model can be used to interpret the carrier transport characteristics in InN thin films.