Dilute-Anion III-Nitride Semiconductor Materials and Nanostructures

Abstract

In this dissertation, the work focuses on the development of the dilute-anion III-Nitride based semiconductor for device applications in visible and deep ultraviolet (UV) spectral regime. First-Principle Density-Functional Theory calculations are employed for the investigation of optoelectronic properties of the dilute-anion III-Nitride semiconductors, which includes the understanding of alloy band structures and related band parameters. Among the dilute-anion III-Nitride semiconductor material class, dilute-As GaNAs, dilute-P GaNP and dilute-As AlNAs are extensively studied in this work. The findings show that the incorporation of anion-content in the GaN or AlN alloy will result in significant changes in the electronic properties, leading to unique features as compared to the conventional III-Nitride alloys such as InGaN and AlGaN alloys. Specifically, the investigation in the electronic properties of dilute-As GaNAs and dilute-P GaNP alloys result in suppression of interband Auger recombination process – a known efficiency-limiting issue in the InGaN quantum well (QW) light emitting diode devices., Further analysis are performed to design novel active region nanostructure of InGaN / dilute-As GaNAs interface QW for visible light emission. The analysis tindicate significantly enhanced spontaneous recombination rate and optical gain across the visible spectral regime from blue to red by using InGaN / dilute-As GaNAs interface QW, as compared to conventional InGaN QW. In the case of dilute-As AlNAs semiconductor, the analysis shows that the incorporation of minute amount of As-content in the AlN alloy will result in the switching of crystal field field split-off band with the heavy hole / light hole band, potentially solving the valence band crossover issue persisting in the AlGaN deep ultraviolet light emitting devices.In addition, extensive studies have been focused in the development of Auger recombination model taking into account the interface roughness in the QW, and analytical solutions for direct Auger recombination processes including interband Auger process for semiconductors. Specifically, the developed Auger model with interface roughness are important to provide intuitive insight of the role of Auger recombination process in the semiconductor devices employing nanostructures