Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

Autor: Tomm JW, Elsaesser T, Talalaev VG, Cirlin GE, Tonkikh AA, Zakharov ND, Werner P, Gösele U
Jazyk: angličtina
Rok vydání: 2006
Předmět:
Zdroj: Nanoscale Research Letters, Vol 1, Iss 2, Pp 137-153 (2006)
Druh dokumentu: article
ISSN: 1931-7573
1556-276X
DOI: 10.1007/s11671-006-9004-x
Popis: AbstractThe luminescence properties of highly strained, Sb-doped Ge/Si multi-layer heterostructures with incorporated Ge quantum dots (QDs) are studied. Calculations of the electronic band structure and luminescence measurements prove the existence of an electron miniband within the columns of the QDs. Miniband formation results in a conversion of the indirect to a quasi-direct excitons takes place. The optical transitions between electron states within the miniband and hole states within QDs are responsible for an intense luminescence in the 1.4–1.8 µm range, which is maintained up to room temperature. At 300 K, a light emitting diode based on such Ge/Si QD superlattices demonstrates an external quantum efficiency of 0.04% at a wavelength of 1.55 µm.
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