Einfluss von Elementen mit kleinen kovalenten Radien auf die (Nano)Struktur von III/V Halbleitermaterialien

本申请研究了新型亚稳态III/V半导体的生长以及定量结构特征，所述新型亚稳态III/V半导体包含具有共价半径和电负性的元素，所述共价半径和电负性与基质原子的共价半径和电负性高度不同。技术相关材料的实例是Ga（NAsP）和（BGa）（AsP）以及Ga（NAsBi），其中氮（N）以及硼（B）显著小于其余合金元素，而Bi（铋）显著较大。这些半导体材料对器件极其重要。稀氮化物和含B材料是直接在硅衬底上的光电III/V材料的集成方案中的候选者。稀释的铋化物在通信波长范围的激光器中具有很大的潜力，在那里它可以最小化损耗，这限制了当今InP基激光器的应用。从基本的观点来看，这些替代原子对局部成键排列以及局部电荷分布的影响的理解也是有趣的。尽管从局部晶格畸变，我们也将阐明结构形成过程，这些材料经历由于与这些元素的合金化。由于B和N或Bi分别占据III/V半导体的相应III族和V族子晶格中的位置，因此还将建立对生长决定III族物质与不一致蒸发的V族物质的效应的理解。具有不同组成的晶体将通过金属有机气相外延生长。不同的透射电子显微镜技术将结合稳定晶体结构的理论描述以及电子衍射的理论建模来应用。这种对量化结构特征的详细、基本的理解也将有助于优化器件性能。

The present application investigates the growth as well as the quantitative structural characteristics of novel metastable III/V semiconductors containing elements with covalent radii and electronegativity, which are highly different from the ones of the matrix atoms. Examples of technologically relevant materials are Ga(NAsP) and (BGa)(AsP) as well as Ga(NAsBi) where nitrogen (N) as well as boron (B) are significantly smaller than the rest of the alloying elements and Bi (bismuth) is significantly larger. These semiconductor materials are extremely important for devices. The dilute nitrides and B-containing materials are candidates in an integration scenario of optoelectronic III/V materials directly on silicon substrates. The dilute bismide has great potential for lasers in the telecommunication wavelength range, where it could minimize the losses, which limit the application of InP-based lasers today. The understanding of the influence of these substitutional atoms on the local bonding arrangement as well as on the local charge distribution is also interesting from fundamental point of view. Despite from the local lattice distortion, we will also clarify structure formation processes, which these materials undergo due to the alloying with these elements. A comprehension of the effects of growth determining group-III species in contrast to incongruently evaporating group-V species will also be established, as B and N or Bi, respectively, occupy positions in the respective group-III and group-V sublattice of the III/V semiconductor. Crystals having different compositions will be grown by metal organic vapour phase epitaxy. Different transmission electron microscopic techniques will be applied in combination with theoretical description of stable crystal structures as well as theoretical modelling of electron diffraction. This detailed, fundamental understanding of the quantified structural characteristics will also help to optimize device performance.