Interlayer excitons(IXS)are electron–hole pairs bound in the spatial separation layer by the Coulomb effect,and their lifetime is several orders of magnitude longer than that of direct excitons,providing an essential...Interlayer excitons(IXS)are electron–hole pairs bound in the spatial separation layer by the Coulomb effect,and their lifetime is several orders of magnitude longer than that of direct excitons,providing an essential platform for long-lived exciton devices.The recent emergence of the van der Waals heterostructure(HS),which combines two layers of different transitional metal dichalcogenides(TMDs),has created new opportunities for IX research.Herein,we demonstrate the observation of double indirect interlayer excitons in the MoSe_(2)/WSe_(2)HS using photoluminescence(PL)spectroscopy.The intensities of the two peaks are essentially the same,and the energy difference is 22 meV,which is perfectly in line with the calculation result of density functional theory.Furthermore,the experience of variable excitation power also proves that the splitting of the IXs originates from the conduction band spin-splitting of MoSe_(2).The observation results provide a promising platform for further exploring the new physical properties and optoelectronic phenomena of TMD HS.展开更多
Van der Waals’two-dimensional(2D)material heterostructure engineering offers an effective strategy for the design of multifunctional and high-performance optoelectronic devices.However,2D heterostructure photodetecto...Van der Waals’two-dimensional(2D)material heterostructure engineering offers an effective strategy for the design of multifunctional and high-performance optoelectronic devices.However,2D heterostructure photodetectors with a photoconductive effect tend to suffer from high driving source-drain voltages and significant dark noise currents.Herein,a self-powered photodetector with high performance was fabricated based on vertically stacked graphene/MoSe_(2)/PdSe_(2)/graphene heterojunctions through a dry transfer method.The fabricated device displays current rectification characteristics in darkness(on/off ratio>10^(3))and superior photovoltaic behaviors under illumination.In addition,benefitting from the strong built-in field,the Gr/PdSe_(2)/MoSe_(2)/Gr heterojunction photodetector is able to respond to a broad spectrum from visible to near-infrared(NIR)with a remarkable responsivity of 651 mA·W^(−1),a high specific detectivity of 5.29×10^(11) Jones and a fast response speed of 41.7/62.5μs.Moreover,an enhanced responsivity of 1.16 A·W^(−1) has been obtained by a reverse voltage(−1 V)and further evaluation on image recognition has also demonstrated the great application potential of the Gr/MoSe_(2)/PdSe_(2)/Gr heterojunction photodetector.The findings are expected to bring new opportunities for the development of highly sensitive,high-speed and energy-efficient photodetectors for comprehensive applications.展开更多
基金the National Natural Science Foundation of China(No.61775241)Hunan province key research and development project(No.2019GK2233)+5 种基金the Hunan Science Fund for Distinguished Young Scholar(No.2020JJ2059)Youth Innovation Team of Central South University(No.2019012)Hunan Province Graduate Research and Innovation Project(No.CX20190177)the Science and Technology Innovation Basic Research Project of Shenzhen(No.JCYJ20180307151237242)Also,Y.P.L.acknowledges the support provided by the Central South University of the State Key Laboratory of High-Performance Complex Manufacturing Project(No.ZZYJKT2020-12)Z.W.L.thanks the funding support from the Australian Research Council(ARC Discovery Projects)(Nos.DP210103539 and DP180102976).
文摘Interlayer excitons(IXS)are electron–hole pairs bound in the spatial separation layer by the Coulomb effect,and their lifetime is several orders of magnitude longer than that of direct excitons,providing an essential platform for long-lived exciton devices.The recent emergence of the van der Waals heterostructure(HS),which combines two layers of different transitional metal dichalcogenides(TMDs),has created new opportunities for IX research.Herein,we demonstrate the observation of double indirect interlayer excitons in the MoSe_(2)/WSe_(2)HS using photoluminescence(PL)spectroscopy.The intensities of the two peaks are essentially the same,and the energy difference is 22 meV,which is perfectly in line with the calculation result of density functional theory.Furthermore,the experience of variable excitation power also proves that the splitting of the IXs originates from the conduction band spin-splitting of MoSe_(2).The observation results provide a promising platform for further exploring the new physical properties and optoelectronic phenomena of TMD HS.
基金the National Natural Science Foundation of China(No.61775241)the Hunan Science Fund for Distinguished Young Scholar(No.2020JJ2059)+5 种基金Hunan Province Key Research and Development Project(No.2019GK2233)Youth Innovation Team(No.2019012)of CSUHunan Province Graduate Research and Innovation Project(No.CX20190177)the Science and Technology Innovation Basic Research Project of Shenzhen(No.JCYJ20180307151237242)Also,Y.P.L.acknowledges the supported by the Project of State Key Laboratory of High-Performance Complex Manufacturing,Central South University(No.ZZYJKT2020-12)Z.W.L.thanks the funding support from the Australian Research Council(ARC Discovery Projects,Nos.DP210103539,DP180102976,and DP130104231).
文摘Van der Waals’two-dimensional(2D)material heterostructure engineering offers an effective strategy for the design of multifunctional and high-performance optoelectronic devices.However,2D heterostructure photodetectors with a photoconductive effect tend to suffer from high driving source-drain voltages and significant dark noise currents.Herein,a self-powered photodetector with high performance was fabricated based on vertically stacked graphene/MoSe_(2)/PdSe_(2)/graphene heterojunctions through a dry transfer method.The fabricated device displays current rectification characteristics in darkness(on/off ratio>10^(3))and superior photovoltaic behaviors under illumination.In addition,benefitting from the strong built-in field,the Gr/PdSe_(2)/MoSe_(2)/Gr heterojunction photodetector is able to respond to a broad spectrum from visible to near-infrared(NIR)with a remarkable responsivity of 651 mA·W^(−1),a high specific detectivity of 5.29×10^(11) Jones and a fast response speed of 41.7/62.5μs.Moreover,an enhanced responsivity of 1.16 A·W^(−1) has been obtained by a reverse voltage(−1 V)and further evaluation on image recognition has also demonstrated the great application potential of the Gr/MoSe_(2)/PdSe_(2)/Gr heterojunction photodetector.The findings are expected to bring new opportunities for the development of highly sensitive,high-speed and energy-efficient photodetectors for comprehensive applications.