This thesis investigates GaAs based single core-shell Nanowire (NW) lasers. Self-catalyzed GaAs NW growth and the effect of their crystal phase on the in-situ thermal decomposition dynamics is examined. It is experimentally shown how an InAlGaAs buffer layer can reduce strain in radial InGaAs multi quantum-wells. Usage of GaAsSb NWs as core reduces strain alike and their growth is successfully developed for usage in NW lasers.weiterlesen