Room-Temperature Broad-Wavelength-Tunable Single-Mode Lasing from Alloyed CdS<sub>1-<i>x</i></sub>Se<sub><i>x</i></sub> Nanotripods.

Guo, Pengfei; Yang, Qian; Shen, Xia; Lv, Qihang; Hao, Yuying; Xiao, Liantuan; Ho, Johnny C; Yu, Kin Man · ACS Nano · 2022

basic_science · Level V

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Abstract

Wavelength-tunable semiconductor nanolasers have attracted tremendous attention for their tunable emissions and robust stability, bringing possibilities for various applications, including nanophotonic circuits, solid-state white-light sources, wavelength-converted devices, and on-chip optical communications. Here, we report on the demonstration of broadband-tunable, single-mode nanolasers based on high-quality alloyed single crystalline CdS<sub>1-<i>x</i></sub>Se<sub><i>x</i></sub> (<i>x</i> = 0-1) nanotripods with well-formed facets fabricated using a conventional CVD approach. Microstructural characterization and optical investigations reveal that these structures are crystalline with composition-tunable CdS<sub>1-<i>x</i></sub>Se<sub><i>x</i></sub> alloys. Microphotoluminescence spectra and mapping of these nanotripods exhibit emissions with continuous wavelengths from 509 to 712 nm, further demonstrating that the CdS<sub>1-<i>x</i></sub>Se<sub><i>x</i></sub> alloys have tunable bandgaps due to the composition gradient. Additionally, under a pulse laser illumination, room-temperature single-mode lasing is clearly observed from these nanotripods cavities, which shows almost identical emission lines with a high-quality factor of ∼1231. More importantly, wavelength continuously tunable nanolasers from 520 to 738 nm are successfully constructed using these bandgap gradient nanotripods. The capability to fabricate high-quality tunable nanolasers represents a significant step toward high-integration optical circuits and photonics communications.