InP/(Al,Ga)InP Quantum Dots on GaAs- and Si-Substrates for Single-Photon Generation at Elevated Temperatures

Religion is an insult to human dignity. Without it you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. (Steven Weinberg 1999) This work concentrates on optical investigation on single-photon generation for applications in communications, quantum cryptography, and quantum computing. Single-photon sources for commercial devices require robustness in their working conditions, e.g. temperature, pressure, etc. as well as high output rates and emission directionality. From the many possibilities of generating single-photons like single-atoms, parametric down-conversion, nitrogen vacancy centers in diamond etc., InP quantum dots have been chosen for detailed analysis in this thesis. The InP and InAs quantum dots discussed in this work, are epitaxially fabricated by MOVPE in the Stranski-Krastanov growth-mode. In order to access a single quantum dot, different approaches of processing and pre-processing like shadow masks, mesas, micro-pillars, and site-controlled growth are employed. The quantum dots have been fabricated on different substrates, namely miscut and exactly oriented GaAs, Si, and Ge virtual substrate on Si. The latter two might allow complementary metal oxide semiconductor (CMOS)-compatibility, which is of high interest because it allows the integration of optical elements into