Energy-efficient Tunable Nanoemitters in a Gated Plasmonic Heterostructure and Its Future Prospects
Dr. Yu-Jung Lu
1Research Center for Applied Sciences, Academia Sinica, No. 128, Sec. 2, Academia Road, Taipei 11529, Taiwan
2Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States
*E-mail: yujunglu@gate.sinica.edu.tw
In this talk, I will present an overview of my research works in recent five years. My previous works mainly focus on wavelength-tunable on-chip nanoemitters, such as InGaN nano-LEDs and InGaN plasmonic nanolasers[1,2]. Here, I will specifically present my recent work during my 2-years Postdoc research in Caltech. I have developed a research project focusing on “Gate Tunable Spontaneous Emission Decay Rate of InP Quantum Dots” and “Organo-lead Halide Perovskite Nanolasers”[3]. I have performed electromagnetic simulations to design gate tunable heterostructures for tuning spontaneous emission from quantum dots, which have been also fabricated and experimentally characterized. The idea is by electrically modulating the titanium nitride (TiN) in the designed plasmonic heterostructure, we demonstrated the field-effect modulated spontaneous emission rate of semiconductor quantum dots due to novel electric-field induced refractive index change mechanism. We demonstrate gate tunable spontaneous emission rate of InP quantum dots (QDs) due to bias induced modification of the local density of optical states (LDOS). The modulation is due to the large change in complex dielectric function at TiN/gate dielectric interface in the bias-induced accumulation/depletion layer. The underlying physics is very promising since by using electric-field induced LDOS modulation, not only bias-induced PL quenching but also bias-induced PL enhancing of semiconductor QDs can be observed. Unlike conventional LED structure which require special doping to make p-n junction or complex growth, this work opens the door towards optoelectronic applications that are simple to implement. This LDOS modulation effect provides an insight in development of tunable on-chip optical light sources for potential future application on electrically driven plasmonic nanolasers, ultracompact on-chip optical information processing, electrical controlled single photon emission, and thin film display.
References
- Y-J Lu et al. “Plasmonic Nanolaser Using Epitaxially Grown Silver Film.” Science 337, 450 (2012).
- Y-J Lu et al. “All-Color Plasmonic Nanolasers with Ultralow Thresholds: Auto-tuning Mechanism for
Single-Mode Lasing.” Nano Lett. 14, 4381(2014).
- Y-J Lu et al. “Tunable Radiative Emission of InP Quantum Dots with Gated TiN/SiO2/Ag Plasmonic
Heterostructure.” (in press) (2017).