The effect of image charges on current transport mechanisms investigated at the nanoscale in Al1􀀀xInxN/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 Al1􀀀xInxN/GaN interface, enhancing electron transport. This barrier lowering depends on the 2DEG characteristics, such as 2DEG density n2D, 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.

Thermionic emission from the 2DEG assisted by image-charge-induced barrier lowering in AlInN/AlN/GaN heterostructures

CAVALCOLI, DANIELA;CAVALLINI, ANNA
2012

Abstract

The effect of image charges on current transport mechanisms investigated at the nanoscale in Al1􀀀xInxN/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 Al1􀀀xInxN/GaN interface, enhancing electron transport. This barrier lowering depends on the 2DEG characteristics, such as 2DEG density n2D, 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.
2012
A. Minj; D.Cavalcoli; A.Cavallini
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/113709
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 8
social impact