Advanced III-nitride materials for next generation UV emitters used in water purification, environmental protection and local network communication

实现可持续的未来需要对自然资源进行良好的管理，也需要保持世界环境的良好状态。这两者对于维持可持续发展都是至关重要的，并且可以通过开发先进材料来促进，这些材料可以制造成改进的紫外线光源。280纳米或亚280纳米紫外光源在建立高标准的基础设施，如水净化，环境保护，局部网络通信，医疗设备去污等方面具有许多重要的应用。因此，获得具有这些功能的高晶体质量的先进材料至关重要，这些材料可以制作成紧凑，重量轻，坚固耐用的280纳米紫外发射器。iii -氮化物半导体合金AlGaN在其整个组成范围内具有直接带隙，覆盖了210 ~ 365 nm紫外光谱的主要部分，是实现这种照明光源的最佳材料体系。在过去十年中，iii -氮化物取得了令人印象深刻的发展。然而，这些成就很大程度上局限于InGaN/GaN材料体系，主要用于制造可见光谱区域的发射器。高铝含量的AlGaN或AlN需要实现280 nm的发射。近十年来，世界范围内对深紫外iii型氮化物材料的研究取得了长足的进展。然而，结果远非令人满意。主要问题是由于目前生长在c平面衬底上的AlGaN或AlN材料。这些极性iii -氮化物半导体材料在科学和技术上导致了许多严重的基本限制，严重限制了深紫外发射器的进一步发展。拟议的项目将结合我们在先进的金属有机气相外延（MOVPE）生长和纳米制造技术（谢菲尔德），iii -氮化物的光学和电子束研究（斯特拉思克莱德），微结构研究（帝国）和先进的氢化物气相外延（HVPE）生长的独立AlN衬底和倒装器件制造（南京，中国）的广泛和互补的经验。联合研究和开发计划旨在实现相互关联的单个问题的理解，然后实现先进的非/半极性AlGaN或AlN，这将应用于新型非/半极性led的演示。我们还致力于开发第一个280 nm的紫外激光二极管（非/半极性ld），而迄今为止报道的最短波长激光二极管仅限于336 nm。

The delivery of a sustainable future needs an excellent management of natural resources and also requires the world's environment to be maintained in good condition. Both of these are crucial for maintaining sustainable development and can be promoted by the development of advanced materials which can be fabricated into improved ultraviolet (UV) light sources. 280 nm or sub-280 nm UV light sources have many important applications in establishing high standard infrastructures, such as water purification, environmental protection, local network communication, medical equipment decontamination, etc.Therefore, it is crucial to obtain advanced materials with these multiple functions in high crystal quality which can be fabricated into compact, light-weight and robust 280 nm UV emitters with high efficiency. The III-nitride semiconductor alloy AlGaN, has a direct bandgap across its entire composition range, covering a major part of the UV spectrum from 210 to 365 nm, and is the best material system to realize such a lighting source. The last decade has seen impressive developments in III-nitrides. However, the achievements are largely limited to the InGaN/GaN material system for the fabrication of the emitters mainly in the visible spectra region. High Al content AlGaN or AlN are required to achieve emission at 280 nm. In the last decade, considerable effort has been to the development of deep-UV III-nitride materials world wide. However, the results are far from satisfactory. The major issue is due to AlGaN or AlN material currently grown on c-plane substrates. These polar III-nitride semiconductor materials lead to a number of severe fundamental limits in science and technology, which are heavily restricting further development of deep UV emitters. The proposed project will combine our extensive and complementary experiences in advanced metal-organic vapour phase epitaxy (MOVPE) growth and nanofabrication technology (Sheffield), optical and electron-beam studies of III-nitrides (Strathclyde), micro-structural investigation (Imperial), and advanced Hydride Vapour Phase Epitaxy (HVPE) growth for free-standing AlN substrate and flip-chip device fabrication (Nanjing, China). The combined research and development programme aims to achieve an understanding of the interrelated individual issues, and then to achieve advanced non/semi-polar AlGaN or AlN which will be applied to the demonstration of a new type of non/semi-polar LEDs. We also aim to develop the first 280 nm UV laser diode (non/semi-polar LDs), while the shortest wavelength laser diode reported so far is limited to 336 nm.