The idea of using the electron spin and charge degree of freedom in semiconductors may lead to create smaller, faster, less power consuming and more versatile devices than currently available chips and circuit elements. Despite the well-established modeling of spin based semiconductor devices, these devices have not been realized due to challenges in injecting and detecting spin of electron in semiconductors. The focus of this research is to study Ge based diluted magnetic semiconductors (DMS) which are good candidates for spin injection into semiconductors and play a key role in semiconductor spintronics due to their room temperature ferromagnetic ordering. Overall goal of this project is to better understand the fundamentals of ferromagnetism in these materials. In this manner, high quality DMS will be grown on technologically significant Si substrates by molecular beam epitaxy with atomic-scale precision. The evolution of the structural and chemical properties will be explored at different stages of the growth by various state-of-the-art insitu microscopy and spectroscopy techniques. The spin resolved electronic structure of the grown films, and their surfaces and interfaces will be investigated with spin and angle resolved photoelectron spectroscopy using synchrotron radiation. Ferromagnetism and its correlations with electronic properties will be investigated through magnetization studies at elevated temperatures and high and low magnetic fields using magneto optical Kerr effect and vibrating sample measurements. An understanding of spin physics arising from this research will lead to the potential development of new spintronic devices such as ultra-sensitive magnetic field sensors, quantum-based logic, and memory and integrated chips for high speed computation. This research project will motivate and encourage graduate students realize a firmer understanding of magnetism, semiconductor physics, and spin-electronic devices.