Effect of doping concentration on the performance of terahertz quantum-cascade lasers

We characterized a set of terahertz quantum-cascade lasers with identical device parameters except for the doping concentration. The δ-doping density was varied from 3.2×1010to4.8×1010cm−2. We observed that the threshold current density increased monotonically with doping. Moreover, the measured res...

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Veröffentlicht in:Applied physics letters 2005-10, Vol.87 (14)
Hauptverfasser: Liu, H. C., Wächter, M., Ban, D., Wasilewski, Z. R., Buchanan, M., Aers, G. C., Cao, J. C., Feng, S. L., Williams, B. S., Hu, Q.
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Sprache:eng
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Zusammenfassung:We characterized a set of terahertz quantum-cascade lasers with identical device parameters except for the doping concentration. The δ-doping density was varied from 3.2×1010to4.8×1010cm−2. We observed that the threshold current density increased monotonically with doping. Moreover, the measured results on devices with different cavity lengths provided evidence that the free carrier absorption caused waveguide loss also increased monotonically. Interestingly, however, the observed maximum lasing temperature displayed an optimum at a doping density of 3.6×1010cm−2.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.2067699