Microstructure and morphology of 2D arrays of Ge quantum dots in a Si/Al₂O₃ matrix

The paper presents the results of the microstructure and morphology study of two-dimensional Ge QD arrays in a Si/Al2O3 matrix formed by annealing multilayer periodic structures with Ge nanolayers in a Si/Al2O3 matrix. The distinctive features of samples in the series are the location and thickness of the Si barrier layers between Ge and aluminium oxide matrix. X-ray reflectometry and diffractometry and transmission electron microscopy studies have shown that large Al₆Ge₅ crystallites are formed and the multilayer structure is destroyed after annealing of the multilayer sample Al₂O₃/Ge without Si. It was found that the presence of Si barrier layers in multilayer Al₂O₃/Si/Ge structures reduces the interdiffusion of Al and Ge, but Ge_1-xSi_x nanocrystallites are formed as a result of Si and Ge interdiffusion. Thus, the introduction of Si barrier layer into the Al₂O₃/Ge structure allowed obtaining of two-dimensional arrays of Ge_1-xSi_x nanocrystallites with the penetration of Si up to 0.64.