Electronic structure modification of Si nanocrystals with F4-TCNQ

A. Carvalho, J. Coutinho, M. Barroso, E. L. Silva, S. Öberg, M. Rayson, and P. R. Briddon
Phys. Rev. B 84, 125437 – Published 19 September 2011
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Abstract

We use first-principles models to demonstrate how an organic oxidizing agent F4-TCNQ (7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane) modifies the electronic structure of silicon nanocrystals, suggesting it may enhance p-type carrier density and mobility. The proximity of the lowest unoccupied level of F4-TCNQ to the highest occupied level of the Si nanocrystals leads to the formation of an empty hybrid state overlapping both the nanocrystal and molecule, reducing the excitation energy to 0.8–1 eV in vacuum. Hence, it is suggested that F4-TCNQ can serve both as a surface oxidant and as a mediator for hole hopping between adjacent nanocrystals in p-type doped silicon nanocrystal networks.

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  • Received 28 July 2011

DOI:https://doi.org/10.1103/PhysRevB.84.125437

©2011 American Physical Society

Authors & Affiliations

A. Carvalho*, J. Coutinho, and M. Barroso

  • Department of Physics, I3N, University of Aveiro, Campus Santiago, P-3810-193 Aveiro, Portugal

E. L. Silva

  • Department of Physics, CEMDRX and CFC, Faculty of Science and Technology, University of Coimbra, Rua Larga, P-3004-516 Coimbra, Portugal

S. Öberg and M. Rayson

  • Department of Engineering Sciences and Mathematics, Luleå University of  Technology, Luleå S-97187, Sweden

P. R. Briddon

  • Electrical, Electronic and Computer Engineering, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, United Kingdom

  • *aicarvalho@ua.pt

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Issue

Vol. 84, Iss. 12 — 15 September 2011

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