Charge Carrier Dynamics and Broad Wavelength Tunable Amplified Spontaneous Emission in Zn x Cd1- xSe Nanowires

Xiaojun Li; Qi Wei; Kaiyang Wang; Shaomin Peng; Tanghao Liu; Guichuan Xing; Zikang Tang

doi:10.1021/acs.jpclett.9b03051

Charge Carrier Dynamics and Broad Wavelength Tunable Amplified Spontaneous Emission in Zn _x Cd_{1- x}Se Nanowires

J Phys Chem Lett. 2019 Dec 5;10(23):7516-7522. doi: 10.1021/acs.jpclett.9b03051. Epub 2019 Nov 25.

Authors

Xiaojun Li¹, Qi Wei¹, Kaiyang Wang¹, Shaomin Peng¹, Tanghao Liu¹, Guichuan Xing¹, Zikang Tang¹

Affiliation

¹ Institute of Applied Physics and Materials Engineering , University of Macau , Avenida da Universidade, Taipa , Macau 999078 , PR China.

PMID: 31729223
DOI: 10.1021/acs.jpclett.9b03051

Abstract

Zn_xCd_1-xSe is regarded as a promising semiconducting material for optoelectronic devices. However, the tunable amplified spontaneous emission (ASE) properties and corresponding charge carrier recombination dynamics in Zn_xCd_1-xSe (0 ≤ x ≤ 1) nanowires (NWs) remain poorly understood. Herein, the charge carrier dynamics and ASE properties in Zn_xCd_1-xSe NWs were systematically investigated. In these NWs, the one/two-photon pumped ASE wavelength across the entire visible spectrum (480-725 nm) can be easily tuned via compositional engineering. The ASE threshold is closely related to the absorption coefficient and PL lifetime. At room temperature, free-carrier recombination is dominated in the low fluence pumped PL process. The ASE behavior is determined by exciton recombination in the high pump fluence (>10¹⁸ cm^-3) region. These findings uncover the origin of the tunable PL/ASE properties in Zn_xCd_1-xSe NWs and establish them as having practical application as a series of lasing gain materials.