Abstract
III-V nitrides have attracted much attention in recently years. InGaN-based blue and green light-emitting diodes (LEDs) and AlGaN/GaN based UV LEDs have long been commercially products. The studies of nano-scaled materials like quantum dots, wells and wires are also topmost interested topics. This thesis tried to study the missed topics and developed the potential technologies among III-V nitrides. In chapter 3, we showed the GaN-based LEDs grown on silicon substrate. The growth mode observation, material properties of GaN grown, and the performance of devices were shown. Besides the academic studies, I hope this technique can be very useful in the future. In chapter 4, we proposed a new growth method called “two-step” growth method for AlGaN grown on sapphire. This technique was well known for GaN grown on sapphire. We not only observed the growth mode step by step, but also found some things interesting during growth, like the Al compositional variation. In chapter 5, we first studied the fundemental properties of InN. The addition of Ga into InN formed In-ruch InGaN alloys. The related topics were proposed: 1. the possibility for phase separation for the In-rich InGaN 2. The field emission of InGaN films 3. the band offsets for InN/GaN interface etc.