单层二硫化钨的荧光特性研究

Photoluminescence properties of monolayer tungsten disulfide

单层二硫化钨的介电屏蔽效应弱,具有大的激子束缚能和强的荧光发射,是直接带隙半导体。利用自制荧光显微光谱成像实验装置对单层二硫化钨进行了荧光性能的测试和分析。结果表明,单层二硫化钨的荧光发射峰处于620nm附近。随着激光功率的增大,单层二硫化钨的荧光强度增大,其荧光发射峰发生明显的红移,且荧光峰位红移量和荧光强度受衬底类型调控。激子行为分析表明,中性激子和带电激子的峰值强度比是衬底依赖的。

Monolayer tungsten disulfide is a direct bandgap semiconductor with weak dielectric screening effect,high exciton binding energy and strong photoluminescence emission.The photoluminescence properties of different monolayer tungsten disulfide samples were measured and analyzed by using a home-built photoluminescence microscopic spectral imaging setup.The results show that the photoluminescence emission peak of monolayer tungsten disulfide is around 620 nm.With the increase of laser power,the photoluminescence intensities increase and the photoluminescence emission peaks of monolayer tungsten disulfide on different substrates exhibit a clear red shift effect.The substrate types can affect the red shift magnitude and the photoluminescence intensities.From the analysis of the excitonic behavior,the results reveal that the peak intensity ratio of the neutral excitons to the charged excitons is substrate dependent.