Monolayer phosphorene provides a unique two-dimensional(2D)platform to investigate the fundamental dynamics of excitons and trions(charged excitons)in reduced dimensions.However,owing to its high instability,unambiguo...Monolayer phosphorene provides a unique two-dimensional(2D)platform to investigate the fundamental dynamics of excitons and trions(charged excitons)in reduced dimensions.However,owing to its high instability,unambiguous identification of monolayer phosphorene has been elusive.Consequently,many important fundamental properties,such as exciton dynamics,remain underexplored.We report a rapid,noninvasive,and highly accurate approach based on optical interferometry to determine the layer number of phosphorene,and confirm the results with reliable photoluminescence measurements.Furthermore,we successfully probed the dynamics of excitons and trions in monolayer phosphorene by controlling the photo-carrier injection in a relatively low excitation power range.Based on our measured optical gap and the previously measured electronic energy gap,we determined the exciton binding energy to be~0.3 eV for the monolayer phosphorene on SiO_(2)/Si substrate,which agrees well with theoretical predictions.A huge trion binding energy of~100 meV was first observed in monolayer phosphorene,which is around five times higher than that in transition metal dichalcogenide(TMD)monolayer semiconductor,such as MoS_(2).The carrier lifetime of exciton emission in monolayer phosphorene was measured to be,220 ps,which is comparable to those in other 2D TMD semiconductors.Our results open new avenues for exploring fundamental phenomena and novel optoelectronic applications using monolayer phosphorene.展开更多
基金financial support from the ANU PhD scholarship,the China Research Council PhD scholarship,the National Science Foundation(USA,grant number ECCS-1405201)the Australian Research Council(grant number DE140100805),and the ANU Major Equipment Committee.
文摘Monolayer phosphorene provides a unique two-dimensional(2D)platform to investigate the fundamental dynamics of excitons and trions(charged excitons)in reduced dimensions.However,owing to its high instability,unambiguous identification of monolayer phosphorene has been elusive.Consequently,many important fundamental properties,such as exciton dynamics,remain underexplored.We report a rapid,noninvasive,and highly accurate approach based on optical interferometry to determine the layer number of phosphorene,and confirm the results with reliable photoluminescence measurements.Furthermore,we successfully probed the dynamics of excitons and trions in monolayer phosphorene by controlling the photo-carrier injection in a relatively low excitation power range.Based on our measured optical gap and the previously measured electronic energy gap,we determined the exciton binding energy to be~0.3 eV for the monolayer phosphorene on SiO_(2)/Si substrate,which agrees well with theoretical predictions.A huge trion binding energy of~100 meV was first observed in monolayer phosphorene,which is around five times higher than that in transition metal dichalcogenide(TMD)monolayer semiconductor,such as MoS_(2).The carrier lifetime of exciton emission in monolayer phosphorene was measured to be,220 ps,which is comparable to those in other 2D TMD semiconductors.Our results open new avenues for exploring fundamental phenomena and novel optoelectronic applications using monolayer phosphorene.
