Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is ...Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is presented to prepare copper halide films with wafer-scale spatial homogeneity.Benefiting from the electric field manipulation method,the built-in electric fields are optimized and further boost the self-powered UV photodetecting performances of common wide-bandgap semiconductors by more than three orders of magnitude.Furthermore,with effective modulation of the interfacial charge dynamics,the as-fabricated GaN-substrate heterojunction photodetector demonstrates an ultrahigh on/off ratio exceeding 107,an impressive responsivity of up to 256 mA W^(-1),and a remarkable detectivity of 2.16×10^(13) Jones at 350 nm,0 V bias.Additionally,the device exhibits an ultrafast response speed(t r/t d=716 ns/1.30 ms),an ultra-narrow photoresponse spectrum with an FWHM of 18 nm and outstanding continuous operational stability as well as long-term stability.Subsequently,a 372-pixel light-powered imaging sensor array with the coefficient of variation of photocurrents reducing to 5.20%is constructed,which demonstrates exceptional electrical homogeneity,operational reliability,and UV imaging capability.This strategy provides an efficient way for large-scale integration of metal halide perovskites with commercial semiconductors for miniature optoelectronic devices.展开更多
Data storage has become an important issue for energy efficient data management in sensor networks. In this paper, we investigate the optimized storage placement problem in large scale sensor networks, aiming to achie...Data storage has become an important issue for energy efficient data management in sensor networks. In this paper, we investigate the optimized storage placement problem in large scale sensor networks, aiming to achieve minimized energy cost. In order to efficiently deal with large scale deployment areas with irregular shape, we propose to utilize the hop as the computation unit instead of the node, such that computation complexity can be greatly reduced. We propose methodologies to solve the optimization problem both in situations for limited and unlimited numbers of storage units. The ultimate goal of this paper is to give fundamental guidance for optimized storage placement in large scale sensor networks. Simulation results show that our methodologies can greatly reduce the overall energy consumption compared to other strategies.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.92263106,62204047,and 12061131009)Science and Technology Commission of Shanghai Municipality(Nos.21520712600 and 19520744300).
文摘Large-scale growth and heterogeneous integration with existing semiconductors are the main obstacles to the application of metal halide perovskites in optoelectronics.Herein,a universal vacuum evaporation strategy is presented to prepare copper halide films with wafer-scale spatial homogeneity.Benefiting from the electric field manipulation method,the built-in electric fields are optimized and further boost the self-powered UV photodetecting performances of common wide-bandgap semiconductors by more than three orders of magnitude.Furthermore,with effective modulation of the interfacial charge dynamics,the as-fabricated GaN-substrate heterojunction photodetector demonstrates an ultrahigh on/off ratio exceeding 107,an impressive responsivity of up to 256 mA W^(-1),and a remarkable detectivity of 2.16×10^(13) Jones at 350 nm,0 V bias.Additionally,the device exhibits an ultrafast response speed(t r/t d=716 ns/1.30 ms),an ultra-narrow photoresponse spectrum with an FWHM of 18 nm and outstanding continuous operational stability as well as long-term stability.Subsequently,a 372-pixel light-powered imaging sensor array with the coefficient of variation of photocurrents reducing to 5.20%is constructed,which demonstrates exceptional electrical homogeneity,operational reliability,and UV imaging capability.This strategy provides an efficient way for large-scale integration of metal halide perovskites with commercial semiconductors for miniature optoelectronic devices.
基金Acknowledgements This work was partially supported by the National Natural Science Foundation of China （Grant Nos. 61100196, 61073028, 61321491, 91218302） and the JiangSu Natural Science Foundation （BK2011559）.
文摘Data storage has become an important issue for energy efficient data management in sensor networks. In this paper, we investigate the optimized storage placement problem in large scale sensor networks, aiming to achieve minimized energy cost. In order to efficiently deal with large scale deployment areas with irregular shape, we propose to utilize the hop as the computation unit instead of the node, such that computation complexity can be greatly reduced. We propose methodologies to solve the optimization problem both in situations for limited and unlimited numbers of storage units. The ultimate goal of this paper is to give fundamental guidance for optimized storage placement in large scale sensor networks. Simulation results show that our methodologies can greatly reduce the overall energy consumption compared to other strategies.
