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

摘要

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 valencehyphen;band mixing in a strained QW, the inhyphen;plane hole mass can become very large or negative. This leads to a heavy electronhyphen;hole reduced mass (exciton mass), and therefore to a small exciton radius. Exciton absorption is substantially increased because of the increased electronhyphen;hole overlap probability in these smallhyphen;radius excitons. The effects of saturation are also substantially reduced because of decreased chargehyphen;screening effects for smallhyphen;radius excitons and because the rapid dispersal of the photonhyphen;generated excitons reduces the Pauli exclusion effect.