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.

在优化了成功的基于GAN的LED以用于可见光发射之后，其他光谱范围越来越多地进入科学焦点。在这个项目中，我们打算专注于短波长紫外线（UV-C）光谱范围的LED，因为灭菌和空气和水的消毒等许多应用都变得越来越有趣。这样的LED需要在ALN（QuASI）底物上生长的Algan异质结构。这种异质结构中的一个主要问题仍然是相当高的缺陷密度，部分原因是不同的单层和所得菌株之间的晶格不匹配引起的。因此，我们打算通过使用硼（b）作为进一步的组成部分来研究如何控制这些问题。已经很小的B分数很小，几％可以帮助大大减少晶格不匹配。但是，由于溶解度相当小，已知B将B掺入被限制。我们将采用高温外延生长，温度高达1400°C，以获得最佳溶解度。我们的调查将阐明这是否确实有助于减少含Al的异质结构的应变，尤其是在含量较大的含量的情况下 - 而不会降低晶体质量和缺陷密度。此外，目前可以使用有关该第四纪材料系统的许多基本属性的稀缺甚至矛盾的信息，例如带隙作为组成的函数，频带偏移，供体和受体电离能量。通过使用样本上各种表征工具的相关方法进行测量，我们将找到此类问题的答案。由六角型BN与MG掺杂的非常有希望的特性的动机，我们还将研究这是否可以导致Albgan层更好地掺杂P。