As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable band...As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable bandgap,high carrier mobility,and excellent air stability.Although 2D MoSe_(2)-based photodetectors have been reported to exhibit admired performance,the large-area 2D MoSe_(2)layers are difficult to be achieved via conventional synthesis methods,which severely impedes its future applications.Here,we present the controllable growth of large-area 2D MoSe_(2)layers over 3.5-inch with excellent homogeneity by a simple post-selenization route.Further,a high-quality n-MoSe_(2)/p-Si van der Waals(vdW)heterojunction device is in-situ fabricated by directly growing 2D n-MoSe_(2)layers on the patterned p-Si substrate,which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W^(−1),a high specific detectivity of 10^(13) Jones,and a fast response time to follow nanosecond pulsed optical signal.In addition,thanks to the inch-level 2D MoSe_(2)layers,a 4×4 integrated heterojunction device array is achieved,which has demonstrated good uniformity and satisfying imaging capability.The large-area 2D MoSe_(2)layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.展开更多
Optical spectral measurements are crucial for optical sensors and many other applications,but the prevailing methods,such as optical spectrum analysis and tunable laser spectroscopy,often have to make compromises amon...Optical spectral measurements are crucial for optical sensors and many other applications,but the prevailing methods,such as optical spectrum analysis and tunable laser spectroscopy,often have to make compromises among resolution,speed,and accuracy.Optical frequency combs are widely used for metrology of discrete atomic and molecular spectral lines.However,they are usually generated by optical methods and have large comb spacing,which limits the resolution for direct sampling of continuous spectra.To overcome these problems,this paper presents an original method to digitally generate an ultrafine optical frequency comb(UFOFC)as the frequency ruler for spectral measurements.Each comb line provides one sampling point,and the full spectrum can be captured at the same time using coherent detection.For an experimental demonstration,we adopted the inverse fast Fourier transform to generate a UFOFC with a comb spacing of 1.46 MHz over a 10-GHz range and demonstrated its functions using a Mach–Zehnder refractive index sensor.The UFOFC obtains a spectral resolution of 0.01 pm and response time of 0.7 μs;both represent 100-fold improvements over the state of the art and could be further enhanced by several orders of magnitude.The UFOFC presented here could facilitate new label-free sensor applications that require both high resolution and fast speed,such as measuring binding kinetics and single-molecule dynamics.展开更多
基金This work was financially supported by the National Key R&D Program of China(No.2022YFB2803900)the National Natural Science Foundation of China(Nos.U2004165,U22A20138,and 11974016)+1 种基金the Natural Science Foundation of Henan Province,China(No.202300410376)Key Research and Development Program(social development)of Jiangsu Province(No.BE2021667).
文摘As one of the most promising materials for two-dimensional transition metal chalcogenides(2D TMDs),molybdenum diselenide(MoSe_(2))has great potential in photodetectors due to its excellent properties like tunable bandgap,high carrier mobility,and excellent air stability.Although 2D MoSe_(2)-based photodetectors have been reported to exhibit admired performance,the large-area 2D MoSe_(2)layers are difficult to be achieved via conventional synthesis methods,which severely impedes its future applications.Here,we present the controllable growth of large-area 2D MoSe_(2)layers over 3.5-inch with excellent homogeneity by a simple post-selenization route.Further,a high-quality n-MoSe_(2)/p-Si van der Waals(vdW)heterojunction device is in-situ fabricated by directly growing 2D n-MoSe_(2)layers on the patterned p-Si substrate,which shows a self-driven broadband photoresponse ranging from ultraviolet to mid-wave infrared with an impressive responsivity of 720.5 mA·W^(−1),a high specific detectivity of 10^(13) Jones,and a fast response time to follow nanosecond pulsed optical signal.In addition,thanks to the inch-level 2D MoSe_(2)layers,a 4×4 integrated heterojunction device array is achieved,which has demonstrated good uniformity and satisfying imaging capability.The large-area 2D MoSe_(2)layer and its heterojunction device array have great promise for high-performance photodetection and imaging applications in integrated optoelectronic systems.
基金Zhaohui Li acknowledges the support of the National Basic Research Programme of China(973)(Project No.2012CB315603)National High Technology 863 Research and Development Program of China(Nos.2013AA013300 and 2013AA013403)+5 种基金the Research Fund for the Doctoral Program of Higher Education of China(20124401110003)National Natural Science Foundation of China(NSFC)(Grant No.61435006)the Program for New Century Excellent Talents in University(NCET-12-0679)in ChinaXuming Zhang acknowledges the NSFC(Grant No.61377068)the Hong Kong Research Grant Council(Grant Nos.PolyU 5327/11E and N_PolyU505/13)the Hong Kong Polytechnic University(Grant Nos.G-YN07,4-BCAL and G-YBBE).
文摘Optical spectral measurements are crucial for optical sensors and many other applications,but the prevailing methods,such as optical spectrum analysis and tunable laser spectroscopy,often have to make compromises among resolution,speed,and accuracy.Optical frequency combs are widely used for metrology of discrete atomic and molecular spectral lines.However,they are usually generated by optical methods and have large comb spacing,which limits the resolution for direct sampling of continuous spectra.To overcome these problems,this paper presents an original method to digitally generate an ultrafine optical frequency comb(UFOFC)as the frequency ruler for spectral measurements.Each comb line provides one sampling point,and the full spectrum can be captured at the same time using coherent detection.For an experimental demonstration,we adopted the inverse fast Fourier transform to generate a UFOFC with a comb spacing of 1.46 MHz over a 10-GHz range and demonstrated its functions using a Mach–Zehnder refractive index sensor.The UFOFC obtains a spectral resolution of 0.01 pm and response time of 0.7 μs;both represent 100-fold improvements over the state of the art and could be further enhanced by several orders of magnitude.The UFOFC presented here could facilitate new label-free sensor applications that require both high resolution and fast speed,such as measuring binding kinetics and single-molecule dynamics.