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

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.