title: Thermionic emission from the 2DEG assisted by image-charge-induced barrier lowering in AlInN/AlN/GaN heterostructures.
abstract: The effect of image charges on current transport mechanisms investigated at the nanoscale in Al(1-x)In(x)N/GaN heterostructures was studied. Current-voltage (I-V) measurements were performed locally using a conductive AFM-tip as a nanoprobe and the conduction mechanism was modeled to explain the observed behavior. This model suggests that current transport is controlled by thermionic emission (TE) of the two-dimensional electron gas (2DEG) across the potential barrier at the heterointerface, where the image charges generated by the 2DEG induce a barrier lowering at the Al(1-x)In(x)N/GaN interface, enhancing electron transport. This barrier lowering depends on the 2DEG characteristics, such as 2DEG density n(2D), first subband energy E₀ and the average distance x₀ of the 2DEG from the interface. By fitting the experimental I-V curves with the present model the 2DEG density was evaluated. The obtained results were in very good agreement with the Hall measurements.
authors.affiliation: Dipartimento di Fisica, Università di Bologna, viale Berti Pichat 6/2, I-40127 Bologna, Italy. albert.minj2@unibo.it
authors.forename: A
authors.initials: A
authors.lastname: Minj
authors.forename: D
authors.initials: D
authors.lastname: Cavalcoli
authors.forename: A
authors.initials: A
authors.lastname: Cavallini