Investigations about the epitaxy of AlBGaN hetero structures for applications in UV-LEDs

AlBGaN 异质结构外延在 UV LED 中的应用研究

• 批准号: 276524601
• 负责人: Professorin Dr. Ute Kaiser
• 金额: --
• 依托单位: Zentrale Einrichtung Elektronenmikroskopie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/276524601?language=en
• 关键词: Investigations; about; epitaxy; AlBGaN; hetero

After having optimized successfully GaN-based LEDs for visible light emission, other spectral ranges move more and more into the scientific focus. In this project, we intend to concentrate on LEDs for the short wavelength ultraviolet (UV-C) spectral range, as many applications like sterilisation and disinfection of air and water become more and more interesting. Such LEDs require AlGaN hetero-structures grown on AlN (quasi) substrates. A major problem in such hetero-structures still is the fairly high defect density, partly caused by the large lattice mismatch between the different single layers and the resulting strain. Therefore, we intend to study how these problems can be managed by using boron (B) as a further component. Already quite small B fractions of a few percent can help reducing the lattice mismatch considerably. However, the incorporation of B into AlGaN is known to be limited because of a fairly small solubility. We will apply high-temperature epitaxial growth with temperatures up to 1400°C to get best solubility. Our investigations will clarify whether this indeed helps to reduce the strain in Al-containing hetero-structures - particularly in those with large Al content - without deteriorating the crystalline quality and defect density. Moreover, only scarce or even contradictory information about many fundamental properties of this quaternary material system such as band gap as function of composition, band offsets, donor and acceptor ionisation energies is currently available. By performing measurements with well-correlated methodology of various characterisation tools on our samples, we will find answers to such questions. Motivated by the very promising properties of hexagonal BN concerning p-doping with Mg, we will additionally investigate, whether this also can lead to better p-doping of AlBGaN layers.

在成功优化基于 GaN 的 LED 的可见光发射之后，其他光谱范围越来越多地成为科学关注的焦点，在这个项目中，我们打算重点关注短波长紫外 (UV-C) 光谱范围的 LED。空气和水的灭菌和消毒等应用变得越来越有趣，此类 LED 需要在 AlN（准）衬底上生长的 AlGaN 异质结构，这种异质结构的一个主要问题仍然是相当高的缺陷。密度，部分是由不同单层之间的大晶格失配和由此产生的应变引起的。因此，我们打算研究如何通过使用硼（B）作为其他成分来解决这些问题。百分比可以帮助显着减少晶格失配，但是，由于溶解度相当小，B 掺入 AlGaN 中受到限制。 1400°C 以获得最佳溶解度，我们的研究将阐明这是否确实有助于减少含铝异质结构中的应变（尤其是铝含量较高的异质结构），而不会降低晶体质量和缺陷密度。通过使用我们的各种表征工具的良好相关方法进行测量，目前甚至可以获得有关该四元材料系统的许多基本特性的矛盾信息，例如作为成分函数的带隙、带偏移、供体和受体电离能。受六方氮化硼在 Mg p 掺杂方面非常有前途的特性的启发，我们将找到这些问题的答案，我们还将进一步研究这是否也能导致 AlBGaN 层更好的 p 掺杂。