Li Xiang, Scharf Einav, Levi Adar, Deree Yinon, Stone David, Remennik Sergei, Banin Uri
The Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
ACS Nano. 2025 Aug 19;19(32):29765-29777. doi: 10.1021/acsnano.5c10168. Epub 2025 Aug 5.
Epitaxial growth of shells on III-V semiconductor quantum dot (QD) cores yields improved fluorescence quantum efficiency and stability toward their implementation in light emission technologies. Here, we control the shell morphology and crystal structure and investigate their effects on the emission properties of heterovalent III-V/II-VI core/shell QDs. This is achieved by tuning the ZnSe shell growth mode from kinetic to thermodynamic regimes via adjusting the precursor reactivity. When combined with high-temperature Ostwald ripening, this approach enables controlled tuning of shell morphology between tetrahedral and spherical-like, accompanied by a transformation of the shell crystal structure from zinc-blende to wurtzite. The position of the III-V cores within the III-V/ZnSe core/shell QDs varies under the different growth modes, being closer to the edge in the former. Moreover, the spherical architecture exhibits a higher photoluminescence quantum yield (PLQY) and improved stability. Such morphological and crystal-type differences directly affect the band alignment and exciton confinement, leading to tunable emission spectra and exciton dynamics, as confirmed by quantum mechanical simulations of the band gap exciton energies. This study deepens the understanding of heteroepitaxial growth and emission control in III-V/II-VI core/shell QDs, enabling advanced QD design toward optimization for diverse light emission applications.
在III-V族半导体量子点（QD）核上外延生长壳层，可提高荧光量子效率，并增强其在发光技术应用中的稳定性。在此，我们控制壳层的形态和晶体结构，并研究它们对异价III-V/II-VI核/壳量子点发光特性的影响。这是通过调整前驱体反应性，将ZnSe壳层生长模式从动力学 regime 调整到热力学 regime 来实现的。当与高温奥斯特瓦尔德熟化相结合时，这种方法能够在四面体状和类球状之间可控地调整壳层形态，同时伴随着壳层晶体结构从闪锌矿到纤锌矿的转变。在不同生长模式下，III-V/ZnSe核/壳量子点中III-V族核的位置会发生变化，在前者中更靠近边缘。此外，球状结构表现出更高的光致发光量子产率（PLQY）和更好的稳定性。这种形态和晶体类型的差异直接影响能带排列和激子限制，导致发射光谱和激子动力学可调，能带隙激子能量的量子力学模拟证实了这一点。这项研究加深了对III-V/II-VI核/壳量子点中外延生长和发光控制的理解，有助于实现先进的量子点设计，以优化各种发光应用。
