Growth and characterization of epitaxial gallium arsenide films on germanium for optoelectronic devices using pulsed laser deposition

III-V compound semiconductors are the materials of choice for most optoelectronic applications. The factor that provides an advantage for the III-V group materials is their direct band gap, which covers the entire spectrum (ultra violet to infrared) providing efficient coupling of photons. In this thesis, successful epitaxial growth of GaAs/Ge has been demonstrated. Pulsed Laser Deposition is chosen because of the better flexibility and cost efficiency it offers over other techniques. The films were grown with different sets of laser parameters such as pulse counts and laser energy. The films were also grown on two different substrate orientations ((111) and (100)) in order to understand the impact of substrate orientation on the defect density, surface morphology and the quality of epitaxy. The samples grown on Ge (111) substrates required relatively lesser pulses for good quality epitaxy compared to the samples grown on Ge (100) substrates. The grown films were characterized using standard techniques. The X-Ray diffraction (XRD) measurements confirmed the epitaxial nature of the films. Surface analysis was made feasible by Scanning Electron Microscope (SEM) images. The observations of Current Voltage (I-V) and Capacitance Voltage (C-V) characteristic curves for the fabricated Schottky diodes confirm the good quality epitaxial nature of the grown films.