Competition of optical transitions between direct and indirect bandgaps in Ge1−xSnx

Temperature-dependent photoluminescence (PL) study has been conducted in Ge1−xSnx films with Sn compositions of 0.9%, 3.2%, and 6.0% grown on Si. The competing between the direct and indirect bandgap transitions was clearly observed. The relative peak intensity of direct transition with respect to t...

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Bibliographic Details
Published in:Applied physics letters 2014-08, Vol.105 (5)
Main Authors: Du, Wei, Ghetmiri, Seyed A., Conley, Benjamin R., Mosleh, Aboozar, Nazzal, Amjad, Soref, Richard A., Sun, Greg, Tolle, John, Margetis, Joe, Naseem, Hameed A., Yu, Shui-Qing
Format: Article
Language:English
Subjects:
Applied physics
Composition
Energy gap
Photoluminescence
Silicon substrates
Temperature dependence
Tin
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Summary:Temperature-dependent photoluminescence (PL) study has been conducted in Ge1−xSnx films with Sn compositions of 0.9%, 3.2%, and 6.0% grown on Si. The competing between the direct and indirect bandgap transitions was clearly observed. The relative peak intensity of direct transition with respect to the indirect transition increases with an increase in temperature, indicating the direct transition dominates the PL at high temperature. Furthermore, as Sn composition increases, a progressive enhancement of direct transition was observed due to the reduction of direct-indirect valley separation, which experimentally confirms that the Ge1−xSnx could become the group IV-based direct bandgap material grown on Si by increasing the Sn content.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4892302