Optical properties and energy transfer in InGaAsN quantum well – InAs quantum dots tunnel injection structures for 1.3 μm emission



Tunnel injection structure consisting of InAs self assembled quantum dots emitting light at the second telecom window at 1.3 μm and an InGaAsN injector quantum well is investigated by means of optical spectroscopy and the results compared to the injector-free reference sample. The photoreflectance measurements, supported by calculations, reveal a complex structure of optical transitions in the system of coupled injector, wetting layer and strain reducing layer. The determined energy structure shows that the tunnelling is possible only through the excited states of quantum dots. Photoluminescence excitation proves the carrier transfer (tunnelling) from the injector to the dots at room temperature. The comparison of photoluminescence spectra confirms the tunnelling efficiency, especially at low temperatures. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)