题目：High-purity, Electrically-driven, and Room-temperature Single-photon Sources

报告人：方伟副教授（浙江大学）

主持人：虞华康副教授

时间：2018年6月13日（星期三）10:00

地点：物理楼（18号楼）二楼213室学术报告厅

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                            物理与光电学院

                             2018年6月6日

附件：

内容摘要：Single-photon sources are indispensable for photonic quantum information technologies. For practical applications, compact as well as scalable single-photon sources, which can operate at room temperature and be electrically excited and controlled, are highly desirable.

Here we explore a single CdSe/CdS core/shell colloidal quantum dot as a quantum emitter in electrically driven single-photon source at room temperature. The solution processed device consists of isolated quantum dots embedded in a PMMA layer between the hole-transport and electron-transport layers. The turn-on voltage of the device is as low as 1.9 V. When the applied voltage is 2.6 V, the second-order temporal correlation function (g⁽²⁾(τ)) is smaller than 0.05 at zero delay without any spectral filtering or background correction, which indicates the generation of high-purity single photons.

The highly suppressed multi-photon-emission probability is attributed to both novel device design and carrier injection/recombination dynamics. The device structure allows efficient electro-excitation of isolated quantum dots and excludes background emission from the hole-transport and electron-transport layers. A quantitative model is developed to illustrate the carrier injection/recombination dynamics of single-dot electroluminescence. The results reveal that the bi-exciton formation is greatly suppressed due to the unique electro-excitation dynamics.

报告人简介：方伟副教授，于1999年在北京大学物理系获得学士学位；2006年在美国西北大学物理和天文系获得博士学位；2006-2008年在美国国家标准技术研究所（NIST）做博士后研究；2009年加入浙江大学光电信息工程学系。他的研究方向主要包括基于胶体量子点的量子光源、基于微纳光纤的光学非线性和量子光源、光学微腔与腔量子电动力学等，在Nature Commun.、PNAS、PRL、JACS、Nano Lett.、Opt. Lett.等学术期刊上发表论文50余篇，SCI引用2600余次。