The emerging Au-assisted exfoliation technique enables the production of a wealth of large-area and high-quality ultrathin two dimensional(2D)crystals.Fast,damage-free,and reliable determination of the layer number of...The emerging Au-assisted exfoliation technique enables the production of a wealth of large-area and high-quality ultrathin two dimensional(2D)crystals.Fast,damage-free,and reliable determination of the layer number of such 2D films can greatly promote layer-dependent physical studies and device applications.Here,an optical method has been developed for simple,high throughput,and accurate determination of the layer number for Au-assisted exfoliated MoS_(2)and WS_(2)films in a broad thickness range.The method is based on quantitative analysis of layer-dependent white light reflection spectra(WLRS),revealing that the intensity of exciton-induced reflection peaks can be used as a clear indicator for identifying the layer number.The simple yet robust method will facilitate fundamental studies on layer-dependent optical,electrical,and thermal properties and device applications of 2D materials.The technique can also be readily combined with photoluminescence(PL)and Raman spectroscopies to study other layer-dependent physical properties of 2D materials.展开更多
基金the Key-Area Research and Development Program of Guangdong Province(No.2020B010169002)the Natural Science Foundation of Guangdong Province(No.2020A1515010885)+1 种基金the Science and Technology Planning Project of Shenzhen Municipality(No.JCYJ20190806142614541)the Key Laboratory Fund(No.61428060205).
文摘The emerging Au-assisted exfoliation technique enables the production of a wealth of large-area and high-quality ultrathin two dimensional(2D)crystals.Fast,damage-free,and reliable determination of the layer number of such 2D films can greatly promote layer-dependent physical studies and device applications.Here,an optical method has been developed for simple,high throughput,and accurate determination of the layer number for Au-assisted exfoliated MoS_(2)and WS_(2)films in a broad thickness range.The method is based on quantitative analysis of layer-dependent white light reflection spectra(WLRS),revealing that the intensity of exciton-induced reflection peaks can be used as a clear indicator for identifying the layer number.The simple yet robust method will facilitate fundamental studies on layer-dependent optical,electrical,and thermal properties and device applications of 2D materials.The technique can also be readily combined with photoluminescence(PL)and Raman spectroscopies to study other layer-dependent physical properties of 2D materials.