Conduction edge strain splitting in Ge-Si quantum wells using EELS

Autor: Philip E. Batson, J. F. Morar
Rok vydání: 1993
Předmět:
Zdroj: Proceedings, annual meeting, Electron Microscopy Society of America. 51:816-817
ISSN: 2690-1315
0424-8201
DOI: 10.1017/s042482010014991x
Popis: Ge/Si quantum well structures show a high hole mobility as the heavy hole bands are shifted to lower energy under bi-axial strain produced by lattice mismatch between the well and the Si substrate. This strain can also split and shift the conduction band edge in the well to below that of Si, producing a Type I quantum well capable of photo-luminescence. In previous work, we have shown that the conduction bandstructure can be obtained using EELS in the relaxed Ge/Si alloy system. Also, we have noticed that the heterojunction band offset can be obtained from EELS because the Si 2p core level is a constant energy reference level throughout the alloy composition. In this report, we show that a detailed fitting of the shape of the Si L2,3 edge can obtain the bi-axial strain splitting of the conduction band edge as a function of position inside a quantum well. This information can then be correlated with annular dark field images of the cross sectioned well.
Databáze: OpenAIRE