Lottigier Pierre, Di Paola Davide Maria, Alexander Duncan T L, Weatherley Thomas F K, Sáenz de Santa María Modroño Pablo, Chen Danxuan, Jacopin Gwénolé, Carlin Jean-François, Butté Raphaël, Grandjean Nicolas
Advanced Semiconductors for Photonics and Electronics Laboratory, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Electron Spectrometry and Microscopy Laboratory, Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Nanomaterials (Basel). 2023 Sep 16;13(18):2569. doi: 10.3390/nano13182569.
In this work, we report on the efficiency of single InGaN/GaN quantum wells (QWs) grown on thin (<1 µm) GaN buffer layers on silicon (111) substrates exhibiting very high threading dislocation (TD) densities. Despite this high defect density, we show that QW emission efficiency significantly increases upon the insertion of an In-containing underlayer, whose role is to prevent the introduction of point defects during the growth of InGaN QWs. Hence, we demonstrate that point defects play a key role in limiting InGaN QW efficiency, even in samples where their density (2-3 × 109 cm-2) is much lower than that of TD (2-3 × 1010 cm-2). Time-resolved photoluminescence and cathodoluminescence studies confirm the prevalence of point defects over TDs in QW efficiency. Interestingly, TD terminations lead to the formation of independent domains for carriers, thanks to V-pits and step bunching phenomena.
在这项工作中，我们报告了在硅（111）衬底上薄（<1 µm）氮化镓缓冲层上生长的单个氮化铟镓/氮化镓量子阱（QW）的效率，该缓冲层具有非常高的位错密度。尽管缺陷密度很高，但我们表明，在插入含铟底层后，量子阱发射效率显著提高，该底层的作用是在氮化铟镓量子阱生长过程中防止点缺陷的引入。因此，我们证明，即使在点缺陷密度（2 - 3×10⁹ cm⁻²）远低于位错密度（2 - 3×10¹⁰ cm⁻²）的样品中，点缺陷在限制氮化铟镓量子阱效率方面也起着关键作用。时间分辨光致发光和阴极发光研究证实了在量子阱效率方面点缺陷比位错更为普遍。有趣的是，由于V型坑和台阶聚束现象，位错终止导致载流子形成独立的区域。
