Band gap dependence of the recombination processes in InAs/GaAs quantum dots studied using hydrostatic pressure

We present the results based upon a systematic study of the properties of quantum dot (QD) lasers with emission wavelengths around 0.98 and 1.3 μm at room temperature and atmospheric pressure. To investigate the radiative and non-radiative components of the threshold current, we studied the temperature and high hydrostatic pressure dependencies of spontaneous and stimulated emission. Although important parameters such as lasing wavelength, QD density, ridge width, cavity length, threshold current density (Jth) varied greatly, we found that all the lasers have nearly the same dependence of the radiative component, Jrad, on band gap when it was tuned by the application of high pressure. It was observed that Jrad increases strongly with band gap. Therefore the different dependencies of Jth are explained in terms of the relative importance of different non-radiative recombination mechanisms, such as Auger recombination and thermal carrier escape. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)