Optically Detected Magnetic Resonance Imaging of Direct Band-Gap Solar Cell Materials
Final Report Abstract
The original goal of this project was the development of experimental techniques for characterizing semiconductor materials with a direct bandgap, such as GaAs, and to use these techniques for designing materials with improved properties. The targeted experimental techniques are combinations of optical spectroscopy and magnetic resonance. With the help of this techniques, we planned to characterize the materials, with particular focus on defects and on the mobility of charge carriers. To enable these experiments, we had to design and build an experimental setup capable of spatially resolved measurements - both optically and in the magnetic resonance domain, and in the direct space as well in the inverse (k-space, momentum space). For this purpose, we designed and built a setup that included a system of magnetic field gradients, a microwave resonator, and the beam path for optical excitation, microscopy and spectroscopic analysis. While the setup was being built, the pandemic forced the university to close the workshops, which were essential for building the mechanical and electrical parts. During this forced closure, we decided that the graduate student assigned to this project should continue his experimental work with an existing setup for laser-assisted magnetic resonance of NV centers in diamond. In this project, he was supported by a Postdoc and together, they obtained a series of useful results that open new research possibilities in quantum information and sensing. In particular, we developed useful new gate operations for quantum computing, a method for the superresolution imaging of NV centers, and we were able to characterize a system that combines nanodiamonds with 2D materials. At the end of 2023, the laboratory had to be closed down, to make it available for new projects prioritized by the physics department.
