Observation of tera-hertz electromagnetic wave emission from InAs/GaAs quantum dots

Summary form only given. The authors propose using the intersubband (ISB)-transition in self-assembled InAs/GaAs quantum dots (QDs) for THz electromagnetic wave emission, by considering the following features of the QDs: the ISB energy spacing corresponds to the photon energy in the THz frequency region, the quantum levels are completely discrete, and whenever the spacing of the quantum levels are not equal to the phonon energy, it is expected that nonradiative ISB-relaxation is greatly suppressed. They utilize a pin diode structure to observe the ISB-emission from the QDs, where both electrons and holes are injected into the QDs, and when the electrons relax from higher quantum levels to lower ones, the ISB-emission can be observed.