Dielectric Thickness Dependence of Carrier Mobility in Graphene with
  HfO2 Top Dielectric

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

We investigate the carrier mobility in mono- and bi-layer graphene with a top HfO2 dielectric, as a function of the HfO2 film thickness and temperature. The results show that the carrier mobility decreases during the deposition of the first 2-4 nm of top dielectric and remains constant for thicker layers. The carrier mobility shows a relatively weak dependence on temperature indicating that phonon scattering does not play a dominant role in controlling the carrier mobility. The data strongly suggest that fixed charged impurities located in close proximity to the graphene are responsible for the mobility degradation.

Related collections

Most cited references 5

Record: found
Abstract: found
Article: found

Is Open Access

The Raman Fingerprint of Graphene

A. K. Geim, A. C. Ferrari, J C Meyer … (2006)

Graphene is the two-dimensional (2d) building block for carbon allotropes of every other dimensionality. It can be stacked into 3d graphite, rolled into 1d nanotubes, or wrapped into 0d fullerenes. Its recent discovery in free state has finally provided the possibility to study experimentally its electronic and phonon properties. Here we show that graphene's electronic structure is uniquely captured in its Raman spectrum that clearly evolves with increasing number of layers. Raman fingerprints for single-, bi- and few-layer graphene reflect changes in the electronic structure and electron-phonon interactions and allow unambiguous, high-throughput, non-destructive identification of graphene layers, which is critically lacking in this emerging research area.

0 comments Cited 1254 times – based on 0 reviews

Preprint

     Review now

Bookmark

Record: found
Abstract: found
Article: found

Is Open Access

Charged Impurity Scattering in Graphene

M Fuhrer, C. Jang, J. Chen … (2007)

Since the experimental realization of graphene1, extensive theoretical work has focused on short-range disorder2-5, ''ripples''6, 7, or charged impurities2, 3, 8-13 to explain the conductivity as a function of carrier density sigma_(n)[1,14-18], and its minimum value sigma_min near twice the conductance quantum 4e2/h[14, 15, 19, 20]. Here we vary the density of charged impurities nimp on clean graphene21 by deposition of potassium in ultra high vacuum. At non-zero carrier density, charged impurity scattering produces the ubiquitously observed1, 14-18 linear sigma_(n) with the theoretically-predicted magnitude. The predicted asymmetry11 for attractive vs. repulsive scattering of Dirac fermions is observed. Sigma_min occurs not at the carrier density which neutralizes nimp, but rather the carrier density at which the average impurity potential is zero10. Sigma_min decreases initially with nimp, reaching a minimum near 4e2/h at non-zero nimp, indicating that Sigma_min in present experimental samples does not probe Dirac-point physics14, 15, 19, 20 but rather carrier density inhomogeneity due to the impurity potential3, 9, 10.

0 comments Cited 217 times – based on 0 reviews

Preprint

     Review now

Bookmark

Record: found
Abstract: found
Article: not found

Oxygen vacancies in high dielectric constant oxide-semiconductor films.

Supratik Guha, Vijay Narayanan (2007)

We provide evidence that the oxygen vacancy is a dominant intrinsic electronic defect in nanometer scaled hafnium oxide dielectric films on silicon, relevant to microelectronics technology. We demonstrate this by developing a general model for the kinetics of oxygen vacancy formation in metal-ultrathin oxide-semiconductor heterostructures, calculating its effect upon the band bending and interfacial oxidation rates and showing good experimental agreement with the predictions.