Limits...
Two-dimensional carrier distribution in top-gate polymer field-effect transistors: correlation between width of density of localized states and Urbach energy.

Kronemeijer AJ, Pecunia V, Venkateshvaran D, Nikolka M, Sadhanala A, Moriarty J, Szumilo M, Sirringhaus H - Adv. Mater. Weinheim (2013)

Bottom Line: A general semiconductor-independent two-dimensional character of the carrier distribution in top-gate polymer field-effect transistors is revealed by analysing temperature-dependent transfer characteristics and the sub-bandgap absorption tails of the polymer semiconductors.A correlation between the extracted width of the density of states and the Urbach energy is presented, corroborating the 2D accumulation layer and demonstrating an intricate connection between optical measurements concerning disorder and charge transport in transistors.

View Article: PubMed Central - PubMed

Affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of the transistor geometry and the 2D and 3D carrier distribution profile in the accumulation layer of the transistors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4230477&req=5

fig01: Schematic representation of the transistor geometry and the 2D and 3D carrier distribution profile in the accumulation layer of the transistors.

Mentions: The Vissenberg-Matters model is based on percolation hopping in an exponential density of localized states (DOS). The model yields a conductivity that increases as a function of carrier density and temperature. In order to arrive at an analytical expression for the source-drain current, Vissenberg and Matters use a carrier density profile in the accumulation layer that decreases quadratically with distance from the dielectric, a distribution referred to as 3D (Figure1, blue profile). Recently, Brondijk et al. analysed the carrier distribution in self-assembled monolayer transistors (SAMFETs) comprising a single layer of semiconductor only 2 nm thick.13 Brondijk et al. developed an analytical model based on a carrier distribution profile in the transistor accumulation layer where the carrier density is constant up to a certain thickness and zero further away from the dielectric, a profile termed 2D (Figure 1, yellow profile). The rationale for this carrier distribution profile in the SAMFET is that there is no space in a 2 nm thick semiconductor to generate the 3D carrier distribution profile. By using a Taylor expansion of the full expression of the source-drain current in the linear regime, the gate voltage dependence of the transistor current in this regime could be approximated by a power-law. A different exponent is found for the 2D and 3D case and the specific variation of the exponent as a function of temperature is utilized to distinguish between the two cases. From the distinction Brondijk et al. conclude that in Si/SiO2 bottom-gate polymer field-effect transistors – based on various semiconductors – the 3D carrier distribution applies. In contrast, in the SAMFET and monolayer transistors of evaporated 6T molecules the 2D case is appropriate.


Two-dimensional carrier distribution in top-gate polymer field-effect transistors: correlation between width of density of localized states and Urbach energy.

Kronemeijer AJ, Pecunia V, Venkateshvaran D, Nikolka M, Sadhanala A, Moriarty J, Szumilo M, Sirringhaus H - Adv. Mater. Weinheim (2013)

Schematic representation of the transistor geometry and the 2D and 3D carrier distribution profile in the accumulation layer of the transistors.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4230477&req=5

fig01: Schematic representation of the transistor geometry and the 2D and 3D carrier distribution profile in the accumulation layer of the transistors.
Mentions: The Vissenberg-Matters model is based on percolation hopping in an exponential density of localized states (DOS). The model yields a conductivity that increases as a function of carrier density and temperature. In order to arrive at an analytical expression for the source-drain current, Vissenberg and Matters use a carrier density profile in the accumulation layer that decreases quadratically with distance from the dielectric, a distribution referred to as 3D (Figure1, blue profile). Recently, Brondijk et al. analysed the carrier distribution in self-assembled monolayer transistors (SAMFETs) comprising a single layer of semiconductor only 2 nm thick.13 Brondijk et al. developed an analytical model based on a carrier distribution profile in the transistor accumulation layer where the carrier density is constant up to a certain thickness and zero further away from the dielectric, a profile termed 2D (Figure 1, yellow profile). The rationale for this carrier distribution profile in the SAMFET is that there is no space in a 2 nm thick semiconductor to generate the 3D carrier distribution profile. By using a Taylor expansion of the full expression of the source-drain current in the linear regime, the gate voltage dependence of the transistor current in this regime could be approximated by a power-law. A different exponent is found for the 2D and 3D case and the specific variation of the exponent as a function of temperature is utilized to distinguish between the two cases. From the distinction Brondijk et al. conclude that in Si/SiO2 bottom-gate polymer field-effect transistors – based on various semiconductors – the 3D carrier distribution applies. In contrast, in the SAMFET and monolayer transistors of evaporated 6T molecules the 2D case is appropriate.

Bottom Line: A general semiconductor-independent two-dimensional character of the carrier distribution in top-gate polymer field-effect transistors is revealed by analysing temperature-dependent transfer characteristics and the sub-bandgap absorption tails of the polymer semiconductors.A correlation between the extracted width of the density of states and the Urbach energy is presented, corroborating the 2D accumulation layer and demonstrating an intricate connection between optical measurements concerning disorder and charge transport in transistors.

View Article: PubMed Central - PubMed

Affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.

No MeSH data available.


Related in: MedlinePlus