| The growth of gallium nitride doped dilute magnetic semiconducting films was studied for use in magneto-optical applications. The specific area of intended use was room temperature ferromagnetic layers for a spintronic device, (the spin polarized light emitting diode). The requirement for these layers is the ability to dope the host gallium nitride film with manganese, while still maintaining good crystallinity and semiconducting properties with the addition of room-temperature ferromagnetic properties. Codoping of the gallium manganese nitride films with oxygen was also investigated.; These materials were fabricated using the molecular beam epitaxy technique, whereby beams of the constituent elements are produced in an ultra high vacuum environment. Molecular beam epitaxy permits a wide range of growth parameters, to best allow for optimization of the prepared layers. The materials were deposited on sapphire and MOCVD gallium nitride substrates, with particular emphasis on the correlation between the growth conditions and the final magnetic, chemical, and structural properties.; Results with GaMnN layers indicate that the growth conditions were very influential on the properties of the films. Magnetic measurements indicate that the best combination of properties were achieved for GaMnN films grown at a temperature of 700°C, containing three atomic percent manganese, and prepared on a commercially available MOCVD GaN substrate. A prototype spintronic device, (the spin polarized light emitting diode) was prepared. Unfortunately, no spin polarized emission was detected from the LED. The lack of polarization was traced to a high spin relaxation rate in the InGaN LED quantum wells. |
