Broad tunability of emission wavelength by strain coupled InAs/GaAs <sub/>1???x</sub> Sb <sub/>x</sub> quantum dot heterostructures

摘要： Tuning of the photoluminescence emission over a wider range of optical telecommunication wavelength (1.38 μm–1.68 μm) has been achieved by employing a GaAs1 ? xSbx capping layer to the strain coupled bilayer InAs quantum dot (QD) heterostructures. It is shown that the modulation of strain between the two dot layers through variation in Sb-content and thickness of the capping layer strongly influence the dot size. The band alignment transformation from type-I to type-II is observed for high Sb-content in the capping layers. In addition, the carrier lifetime is improved by a factor of three in the QD heterostructures having type-II band alignment. This, we believe, is of importance for optoelectronic device applications.