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Low Threshold Fabry-Pérot Mode Lasing from Lead Iodide Trapezoidal Nanoplatelets
Yangguang Zhong1,2, Qi Wei1,2, Zhen Liu2
1Key Laboratory of Flexible Electronics and Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, 30 South Puzhu Road, Nanjing, 211816, China.
Abstract:
Lead Iodide (PbI2 ) is a layered semiconductor with direct band gap holding great promises in green light emission and detection devices. Recently, PbI2 planar lasers are demonstrated using hexagonal whispering-gallery-mode microcavities, but the lasing threshold is quite high. In this work, lasing from vapor phase deposition derived PbI2 trapezoidal nanoplatelets (NPs) with threshold that is at least an order of magnitude lower than the previous value is reported. The growth mechanism of the trapezoidal NPs is explored and attributed to the synergistic effects of van der Waals interactions and lattice mismatching. The lasing is enabled by the population inversion of n = 1 excitons and the optical feedback is provided by the Fabry-Pérot oscillation between the side facets of trapezoidal NPs. The findings not only advance the understanding of growth and photophysics mechanism of PbI2 nanostructures but also provide ideas to develop low threshold ultrathin lasers.
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