Dynamically controlled Purcell enhancement of visible spontaneous emission in a gated plasmonic heterostructure

• Published in: Nature communications Vol. 8; no. 1; pp. 1631 - 8
• Main Authors: Lu, Yu-Jung, Sokhoyan, Ruzan, Cheng, Wen-Hui, Kafaie Shirmanesh, Ghazaleh, Davoyan, Artur R., Pala, Ragip A., Thyagarajan, Krishnan, Atwater, Harry A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21.11.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1075/401; 639/624/399/1017; 639/624/400/1021; Colloids; Emissions; Emissions control; ENGINEERING; Field emission; Humanities and Social Sciences; Injection current; Luminous intensity; Modulation; multidisciplinary; Optical pumping; Optoelectronic devices; Quantum dots; Quantum theory; Science; Science (multidisciplinary); Silicon dioxide; Spontaneous emission; Titanium nitride
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-01870-0

Emission control of colloidal quantum dots (QDs) is a cornerstone of modern high-quality lighting and display technologies. Dynamic emission control of colloidal QDs in an optoelectronic device is usually achieved by changing the optical pump intensity or injection current density. Here we propose and demonstrate a distinctly different mechanism for the temporal modulation of QD emission intensity at constant optical pumping rate. Our mechanism is based on the electrically controlled modulation of the local density of optical states (LDOS) at the position of the QDs, resulting in the modulation of the QD spontaneous emission rate, far-field emission intensity, and quantum yield. We manipulate the LDOS via field effect-induced optical permittivity modulation of an ultrathin titanium nitride (TiN) film, which is incorporated in a gated TiN/SiO 2 /Ag plasmonic heterostructure. The demonstrated electrical control of the colloidal QD emission provides a new approach for modulating intensity of light in displays and other optoelectronics. The dynamic control of light emission from quantum dots is generally controlled via optical or electrical pumping. Here, Lu et al. electrically control the local density of states around a quantum dot to modulate its visible light emission properties.