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http://hdl.handle.net/2445/49046
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 Semiconductors Electrònica quàntica Nanoelectrònica Teoria quàntica Optoelectrònica Electron transport Semiconductors Quantum electronics Nanoelectronics Quantum theory Optoelectronics |
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: http://dx.doi.org/ 10.1103/PhysRevB.88.075322 |
It is part of: | Physical Review B, 2013, vol. 88, num. 7, p. 075322-1-075322-11 |
URI: | http://hdl.handle.net/2445/49046 |
ISSN: | 1098-0121 |
Appears in Collections: | Articles publicats en revistes (Enginyeria Electrònica i Biomèdica) Publicacions de projectes de recerca finançats per la UE |
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627795.pdf | 2.56 MB | Adobe PDF | View/Open |
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