Investigation of MBE grown inverted GaAs quantum dots

In this work, we investigate the formation of the inverted technology created quantum dot by a method based on droplet epitaxy. The preparation process of the so called inverted quantum dot is carried out with the filling of the nano-hole. The investigated GaAs dot is embedded in AlAs/AlxGa1 − xAs multilayer structure. Transmission electron microscopy investigation shows that the quantum structure is perfectly crystalline and fits very well to the crystal structure of the base layer. The nano-hole has a hill around its opening. Furthermore, the sides of the nano-structure consist of low Miller index facets. The filling process results formation of a hill over the nano-hole. The elemental mapping shows Al immigration into the GaAs layer. Formation of the hill after the filling process and the Al immigration are also explained in this paper. Temperature dependent photoluminescence spectra were measured in the range of room temperature and 4.7 K. The electronic structure given from photoluminescence spectroscopy is explained.