Polarization resolved absorption spectra of a strain-compensated Ge multiple quantum well (MQW) structure with Ge-rich SiGe barriers have been calculated with an sp3d5s∗ tight-binding model and measured for light propagating perpendicular to the growth direction. The MQW was grown by low-energy plasma-enhanced chemical vapor deposition and consists of 50 Ge quantum wells deposited onto a thick graded Si1−xGex buffer layer. The MQW was structurally characterized by high-resolution x-ray diffraction. The measured absorption spectra show clear quantum confined excitonic transitions related to the Ge Γ point band gap, and strong dependence on the incident light polarization, as expected from selection rules for type I direct gap quantum confined systems. A good agreement between theoretically predicted spectra and experimental data is found, demonstrating light and heavy hole polarization-dependent selection rules in Ge MQWs.
|Autori:||Virgilio M; Bonfanti M; Chrastina D; Neels A; Isella G; Grilli E; Guzzi M; Grosso G; Sigg H; von Kanel H|
|Titolo:||Polarization-dependent absorption in Ge/SiGe multiple quantum wells: Theory and experiment|
|Anno del prodotto:||2009|
|Digital Object Identifier (DOI):||10.1103/PhysRevB.79.075323|
|Appare nelle tipologie:||1.1 Articolo in rivista|