Enhanced exciton absorption and saturation limit in strained InGaAs/InP quantum wells

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Abstract
A new approach for enhancing the exciton absorption and increasing the saturation limit in quantum wells (QWs), using tensile strain, is proposed. Because of the valence‐band mixing in a strained QW, the in‐plane hole mass can become very large or negative. This leads to a heavy electron‐hole reduced mass (exciton mass), and therefore to a small exciton radius. Exciton absorption is substantially increased because of the increased electron‐hole overlap probability in these small‐radius excitons. The effects of saturation are also substantially reduced because of decreased charge‐screening effects for small‐radius excitons and because the rapid dispersal of the photon‐generated excitons reduces the Pauli exclusion effect.