M. Sc. Michael Deppe, AG As
What is the challenge of my research project?
My focus is the fabrication of cubic group III-nitrides by plasma-assisted molecular beam epitaxy. Since the growth of the metastable cubic phase only occurs in a small process window, precise control of the growth conditions is required. As a benefit, spontaneous and piezoelectric polarization fields, which occur in the thermodynamically stable hexagonal III-nitrides, are absent in the cubic III-nitrides. This effect can improve the performance of devices.
In the framework of project B02 I fabricate cubic GaN/Al(Ga)N heterostructures which feature intersubband transitions in the near-infrared spectral region. These structures are used to investigate nonlinear properties of the material. By employing germanium as a novel donor for the cubic nitrides, I aim to achieve a strengthening of these effects.
Besides the fabrication of samples, also the characterization plays a significant role for the work in my project. Different techniques like X-ray diffraction, atomic force microscopy and photoluminescence spectroscopy are utilized to analyze and improve the quality of the structures.
Why am I eager to do it? Why did I chose this project?
Molecular beam epitaxy is a powerful but challenging technology. Together with the manifold techniques for analysis of samples, it offers a highly interesting and diversified opportunity to explore new semiconductor structures and their applications.