Telecommunication band InAs quantum dots and dashes embedded in different barrier materials
We investigate the long wavelength (1.2 to 1.55 micro m) photoluminescence of high density InAs quantum dots and dashes, which were grown on InP substrates. We analyze the temperature dependence of the recombination and carrier distribution on the alloy composition of the barrier materials, InGaAlAs, and on the existence of a wetting layer. Carrier escape and transfer are discussed based on temperature dependent photoluminescence measurements and theoretical considerations about the heterostructures' confinement energies and band structure. We propose two different contributions to the thermal quenching, which can explain the observations for both the quantum dot and dash samples. Among these one is a unique phenomenon for high density quantum dot/dash ensembles which is related to significant inter dot/dash coupling. With the goal ahead to use these dots and dashes for quantum optical applications on the single dot/dash level in the telecommunication C band as well as at elevated temperatures we present first steps towards the realization of such devices.