Browsing by Author "Moon, Jiyoung"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Metal Halide Perovskite Light Sources for On-chip Applications(2021-11-10) Moon, Jiyoung; Gu, QingMetal halide perovskites have attracted much attention as economical gain materials for light emitting diodes (LEDs) and on-chip lasers in photonic integrated circuits. However, the potential commercialization of these perovskite light sources has been hindered by the lack of a systematic approach to overcome perovskite instability, and in the case of lasers, the challenge to directly pattern perovskites into resonators. The goals for this dissertation are to establish systematic approaches to stabilize perovskites, and to demonstrate economical perovskite lasers. To understand the importance of the abovementioned goals, the requirements and fundamentals of on-chip light sources are first discussed. Next, a detailed study of the degradation mechanisms in perovskites is presented. Perovskites degrade by exposure to high temperature, ambient atmosphere, polar solvents (e.g., water), and high photo-/e-beam energy which are used in conventional lithography (e.g., photo-/e-beam lithography). Because of the instability of perovskites, we face not only the short shelf life of perovskite devices, but also the difficulty in the direct patterning of perovskites into an optical cavity. In order to improve the shelf life of perovskite devices, a practical encapsulation method as well as its comparison to other common encapsulation methods are presented. To create laser cavities, a novel direct-patterning method of perovskite — nanoimprint lithography — is presented. We show that nanoimprint lithography improves the quality of perovskites and explain the mechanism behind the positive effects of nanoimprint lithography. With a synergistic approach which includes a practical encapsulation method, an efficient patterning method that also improves material morphology, and a high-quality cavity design, the first demonstration of quasi-CW lasing from directly patterned perovskites is shown. Finally, future directions for improving the efficiency of optically pumped perovskite lasers and the realization of electrically pumped perovskite lasers are discussed.Item Nanoimprinted Perovskite Metasurface for Enhanced Photoluminescence(Optical Soc Amer, 2018-11-05) Wang, Honglei; Liu, Shih-Chia; Balachandran, Balasubramaniam; Moon, Jiyoung; Haroldson, Ross; Li, Zhitong; Ishteev, Artur; Gu, Qing; Zhou, Weidong; Zakhidov, Anvar A.; Hu, Wenchuang (Walter); 0000 0003 5287 0481 (Zakhidov, AA); 0000-0003-3983-2229 (Zakhidov, AA); Wang, Honglei; Balachandran, Balasubramaniam; Moon, Jiyoung; Haroldson, Ross; Li, Zhitong; Gu, Qing; Zakhidov, Anvar A.; Hu, Wenchuang (Walter)Recently, solution-processed hybrid halide perovskite has emerged as promising materials for advanced optoelectronic devices such as photovoltaics, photodetectors, light emitting diodes and lasers. In the mean time, all-dielectric metasurfaces with high-index materials have attracted attention due to their low-loss and high-efficient optical resonances. Because of its tunable by composition band gap in the visible frequencies, organolead halide perovskite could serve as a powerful platform for realizing high-index, low-loss metasurfaces. However, direct patterning of perovskite by lithography-based technique is not feasible due to material instability under moisture. Here we report novel organolead halide perovskite metasurfaces created by the cost-effective thermal nanoimprint technology. The nanoimprinted perovskite metasurface showed improved surface morphology and enhanced optical absorption properties. Significantly enhanced optical emission with an eight-fold enhancement in photoluminescence (PL) intensity was observed under room temperature. Temperature-dependent PL of perovskite nanograting metasurface was also investigated. Based on our results, we believe that thermal nanoimprint is a simple and cost-effective technique to fabricate perovskite-based metasurfaces, which could have broad impact on optoelectronic and photonic applications.Item Room Temperature Operation of Directly Patterned Perovskite Distributed Feedback Light Source under Continuous-Wave Optical Pumping(Institute of Electrical and Electronics Engineers Inc.) Gharajeh, Abouzar; Haroldson, Ross; Li, Zhitong; Moon, Jiyoung; Balachandran, Balasubramaniam; Hu, Wenchuang (Walter); Zakhidov, Anvar A.; Gu, Qing; 0000 0003 5287 0481 (Zakhidov, AA); 0000-0003-3983-2229 (Zakhidov, AA); 0000-0003-3855-3690 (Gu, Q); Gharajeh, Abouzar; Haroldson, Ross; Li, Zhitong; Moon, Jiyoung; Balachandran, Balasubramaniam; Hu, Wenchuang (Walter); Zakhidov, Anvar A.; Gu, QingWe report the first directly patterned perovskite distributed feedback (DFB) resonator with a narrow amplified spontaneous emission (ASE) at pump powers as low as 0.1W/cm², under continuous-wave (CW) optical pumping condition at room temperature.