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Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells

Umit Ozgur·Henry O. Everitt·Stacia Keller·Steven P. DenBaars
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Abstract

Stimulated emission (SE) was measured from two InGaN multiple quantum well (MQW) laser structures with different In compositions. SE threshold power densities (I_th) increased with increasing QW depth (x). Time-resolved differential transmission measurements mapped the carrier relaxation mechanisms and explained the dependence of I_th on x. Carriers are captured from the barriers to the QWs in < 1 ps, while carrier recombination rates increased with increasing x. For excitation above I_th an additional, fast relaxation mechanism appears due to the loss of carriers in the barriers through a cascaded refilling of the QW state undergoing SE. The increased material inhomogeneity with increasing x provides additional relaxation channels outside the cascaded refilling process, removing carriers from the SE process and increasing I_th.

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Umit Ozgur, Henry O. Everitt, Stacia Keller, Steven P. DenBaars. 2002-10-16. Stimulated emission and ultrafast carrier relaxation in InGaN multiple quantum wells. https://doi.org/10.1063/1.1557770

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