Optical absorption and electrical conductivity in amorphous Ge/SiOx superlattices

✍ Scribed by A. Bittar; G.V.M. Williams; H.J. Trodahl

• Book ID: 103893663
• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 342 KB
• Volume: 157
• Category: Article
• ISSN: 0378-4371
• DOI: 10.1016/0378-4371(89)90336-1

✦ Synopsis

We have produced high quality amorphous Ge/SiO, superlattice films with periods ranging from 2 to 30 nm. Normal incidence optical spectroscopy is used to determine the effectivemedium absorption edge, identical in this geometry to the interband edge in the narrow band gap layers (Ge). The edge shows a blue shift associated with quantum confinement in Ge layers thinner than 5 nm. A simple Kronig-Penney model fits the results if we assume conduction-and valence-band edge discontinuities of 1.1 and 0.3eV, respectively. DC conductivity measurements parallel to the layers show the effects of 2D confinement on hopping conductivity.