Dielectric Thin-Films by Ion-Beam Sputtering Deposition for III-V Based Infrared Optoelectronic Imaging

The growing technological industry is demanding the development of powerful and smaller devices. Dielectric thin-films can play an important role to help push towards achieving these goals. However, their advantage of high-quality material and low material costs compared to bulk can only be achieved with consideration of the technique, conditions, and parameters. The sensitivity makes every step in the process extremely important, beginning from substrate preparation to the first initial layers of growth and ending with the testing/modeling of the devices. Further, not all applications want bulk-like properties, so the ability to adjust and fine tune the material characteristics opens up a wide range of opportunities with the advancements and can drive the power of the devices to an ultimate level. This work provides the motivation, theoretical basis, and experimental results for performance enhancement of optoelectronic devices through the use of high-quality dielectric thin-films by ion-beam sputtering deposition (IBSD). The advantages and disadvantages to this technique are demonstrated and compared to others. The optimization processes, relationships, and motivation of using seven different thin-film materials have been detailed and provided. Using IBSD, the performance improvements were demonstrated on infrared lasers and detectors. For lasers, a 170% increase in maximum output power was achieved using near-0% percent anti-reflection coatings (AR) and near-100% high-reflection (HR) coatings. Following, wide tunability was achieved by using the structures in an external cavity laser system, showing nearly a three-fold improvement in tuning range. Also, structurally robust lasers were achieved with a custom-tailored HR structure designed for damage resistance to high output power density operation, showing over 14W of peak output power for MOCVD lasers. For infrared photodetectors, over a 4 orders of magnitude decrease in current density and zero-bias resistance area product values on the same order of magnitude as bulk are achieved with passivation that was ne tuned in its electrical behavior. In addition, 62% improvement in quantum efficiency for room temperature operation of the detectors was shown with the utilization of a broadband AR coating. Finally, applications of the principles and physics for future work in UV based devices are discussed.