Semiconductor hyperbolic metamaterials for the infrared
Date
2019
Authors
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Publisher
University of Delaware
Abstract
Light is one of the most important media to transport information. Optical metamaterials are artificial materials that are fabricated on the subwavelength scale so people can manipulate light-matter interactions in a fascinating way that conventional materials are not able to. Optical metamaterials have unique optical properties and may find applications in subwavelength imaging, novel waveguiding, thermal emission engineering, and biosensing, ☐ Multilayer hyperbolic metamaterial (HMM) is one kind of optical metamaterials that are composed of alternating metal/dielectric layers. They are easy to fabricate and have designer properties. Though there are extensive studies about HMM in the visible range, the potential of HMM in the infrared remains to be fully discovered. To move HMM study to the infrared, we first need to choose suitable materials. III-V semiconductors, such as InAs, have been proven to be promising plasmonic materials for the infrared. ☐ This dissertation demonstrates semiconductor HMMs created from various material classes: Si:InAs/InAs, Si:InGaAs/InAlAs, and Si:InAs/AlSb. Discontinuity of the Brewster angle and negative refraction, two hallmarks of HMM, were observed in our materials. Also, the properties of semiconductor HMM are designer by adjusting the structure parameters. ☐ This dissertation also explores the volume plasmon polariton (VPP) modes in semiconductor HMMs. VPP modes are modes with large wavevectors and are usually not supported by conventional materials. They are the foundation of many proposed applications based on HMMs. Up to five VPP modes were observed in our materials, and we found that Si:InAs/AlSb HMM exhibits the best VPP modes among all other semiconductor HMMs. ☐ We also investigated the optimization of the growth of highly Si-doped InAs by using bismuth surfactant. We show that the optical properties, electrical properties and surface morphology of Si:InAs were significantly improved. The growth window of Si:InAs is broadened, making it easier to integrate Si:InAs with other III-V semiconductors. ☐ In the future, III-V semiconductor HMMs will be integrated with other semiconductor structures, including quantum wells, quantum dot, and quantum cascade laser. Such compound structures will lead to new physical phenomena and novel optoelectronic devices with higher efficiency.