Epitaxially-grown quantum dots (QDs) play an essential role in various quantum photonic technologies as on-demand solid-state single-photon sources. However, these QDs often suffer from the adjacent unintentional emitters such as wetting layers and other adjacent QDs, which attribute to the background noise of the QD emission and fundamentally limit the single-photon purity. Here, we develop a nanoscale site-selective luminescence quenching method using focused ion beam (FIB) and demonstrate improved single-photon purity from site-controlled single QD. Moreover, the reduced background noise led to QD emissions at higher temperatures. This nondestructive method retains the photonic structure and quenches the unwanted luminescence simultaneously, thereby indicating its promising potential in quantum emitters integrated with photonic devices.
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