Ryzhak Diana, Aberl Johannes, Prado-Navarrete Enrique, Vukušić Lada, Corley-Wiciak Agnieszka Anna, Skibitzki Oliver, Zoellner Marvin Hartwig, Schubert Markus Andreas, Virgilio Michele, Brehm Moritz, Capellini Giovanni, Spirito Davide
IHP-Leibniz-Institut für innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany.
Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria.
Nanotechnology. 2024 Oct 7;35(50). doi: 10.1088/1361-6528/ad7f5f.
We investigate the nanoheteroepitaxy (NHE) of SiGe and Ge quantum dots (QDs) grown on nanotips (NTs) substrates realized in Si(001) wafers. Due to the lattice strain compliance, enabled by the nanometric size of the tip and the limited dot/substrate interface area, which helps to reduce dot/substrate interdiffusion, the strain and SiGe composition in the QDs could be decoupled. This demonstrates a key advantage of the NHE over the Stranski-Krastanow growth mechanism. Nearly semi-spherical, defect-free, ∼100 nm wide SiGe QDs with different Ge contents were successfully grown on the NTs with high selectivity and size uniformity. On the dots, thin dielectric capping layers were deposited, improving the optical properties by the passivation of surface states. Intense photoluminescence was measured from all samples investigated with emission energy, intensity, and spectral linewidth dependent on the SiGe composition of the QDs and the different capping layers. Radiative recombination occurs in the QDs, and its energy matches the results of band-structure calculations that consider strain compliance between the QD and the tip. The NTs arrangement and the selective growth of QDs allow to studying the PL emission from only 3-4 QDs, demonstrating a bright emission and the possibility of selective addressing. These findings will support the design of optoelectronic devices based on CMOS-compatible emitters.
我们研究了在硅（001）晶圆中实现的纳米尖端（NTs）衬底上生长的硅锗（SiGe）和锗量子点（QDs）的纳米异质外延（NHE）。由于尖端的纳米尺寸和有限的量子点/衬底界面面积所实现的晶格应变顺应性，这有助于减少量子点/衬底的相互扩散，量子点中的应变和SiGe成分可以解耦。这证明了NHE相对于斯特兰斯基-克拉斯塔诺夫生长机制的一个关键优势。具有不同锗含量的近半球形、无缺陷、宽度约为100 nm的SiGe量子点成功地以高选择性和尺寸均匀性生长在NTs上。在量子点上沉积了薄的介电覆盖层，通过钝化表面态改善了光学性能。对所有研究的样品测量了强烈的光致发光，其发射能量、强度和光谱线宽取决于量子点的SiGe成分和不同的覆盖层。辐射复合发生在量子点中，其能量与考虑量子点和尖端之间应变顺应性的能带结构计算结果相匹配。NTs的排列和量子点的选择性生长使得能够仅研究3 - 4个量子点的光致发光发射，展示了明亮的发射以及选择性寻址的可能性。这些发现将支持基于CMOS兼容发射极的光电器件的设计。
