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Title: Silicon quantum dots embedded in a SiO2 matrix: From structural study to carrier transport properties
Author: Garcia-Castello, Nuria
Illera Robles, Sergio
Guerra, Roberto
Prades García, Juan Daniel
Ossicini, Stefano
Cirera Hernández, Albert
Keywords: Transport d'electrons
Electrònica quàntica
Teoria quàntica
Electron transport
Quantum electronics
Quantum theory
Issue Date: 30-Aug-2013
Publisher: American Physical Society
Abstract: We study the details of electronic transport related to the atomistic structure of silicon quantum dots embedded in a silicon dioxide matrix using ab initio calculations of the density of states. Several structural and composition features of quantum dots (QDs), such as diameter and amorphization level, are studied and correlated with transport under transfer Hamiltonian formalism. The current is strongly dependent on the QD density of states and on the conduction gap, both dependent on the dot diameter. In particular, as size increases, the available states inside the QD increase, while the QD band gap decreases due to relaxation of quantum confinement. Both effects contribute to increasing the current with the dot size. Besides, valence band offset between the band edges of the QD and the silica, and conduction band offset in a minor grade, increases with the QD diameter up to the theoretical value corresponding to planar heterostructures, thus decreasing the tunneling transmission probability and hence the total current. We discuss the influence of these parameters on electron and hole transport, evidencing a correlation between the electron (hole) barrier value and the electron (hole) current, and obtaining a general enhancement of the electron (hole) transport for larger (smaller) QD. Finally, we show that crystalline and amorphous structures exhibit enhanced probability of hole and electron current, respectively.
Note: Reproducció del document publicat a: 10.1103/PhysRevB.88.075322
It is part of: Physical Review B, 2013, vol. 88, num. 7, p. 075322-1-075322-11
ISSN: 1098-0121
Appears in Collections:Articles publicats en revistes (Electrònica)
Publicacions de projectes de recerca finançats per la UE

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