Extended optical properties beyond band-edge of GaAs by InAs quantum dots and quantum dot molecules

Abstract

We have reported the optical properties including spectral response and photoluminescence (PL) measurements of conventional quantum dots (QDs) and high-density quantum dot molecules (HD-QDMs). For the extended spectral response beyond band-edge of GaAs, 15-stack conventional InAs QDs give peak centered at 907 nm while 3-stack InAs HD-QDMs give broad peak between 915 and 985 nm. Moreover, extended spectral response from HD-QDMs is also higher and broader than that from QDs. It is found from the PL result that the peak and full width at half maximum (FWHM) from HD-QDMs are also higher and broader than those of conventional QDs. The agreement of these two optical behaviors could be explained by lower dot size uniformity and higher dot density of HD-QDMs sample.