Influence of graded interfaces on the exciton energy of type-I and type-II Si/Si1-x Gex quantum wires

• Published in: Journal of materials science Vol. 42; no. 7; pp. 2314 - 2317
• Main Authors: CHAVES, Andrey, E SILVA, Jusciane Da Costa, DE KING FREIRE, José Alexander, DEGANI, Marcos Henrique, NOGUEIRA FREIRE, Valder, DE AQUINO FARIAS, Gil
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Heidelberg Springer 01.04.2007
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Quantum wires; Interfaces; Quantum wires; Fluctuations; Electron-hole recombination; Excitons; Variational methods; Charge carrier recombination; Ge-Si alloys; Silicon; Spectral line shift
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-006-0617-3

The exciton properties of Si/Si1-xGex cylindrical quantum wires (QWRs) are calculated using the variational method and taking into account the existence of an interface layer between the materials. We consider two possibilities for the conduction band lineup, type-I and type-II. Our numerical results show that an interfacial fluctuation of 15A in a SiO.85Ge0.15 (SiO.70Ge0.30) type-I (type-11) wire of 50A wire radius leads to an exciton energy blue shift of the order of 10 (10) meV.