Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this s...Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this study,abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard templates.The impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional(0D)hexagonal close-packed(hcp)-face-centered cubic(fcc)Co/two-dimensional(2D)Co(OH)_(2)nanosheets@three-dimensional(3D)porous carbon nanosheets(Co/Co(OH)_(2)@PCN).By controlling the carbonization temperature,the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth(EAB).Accordingly,the EAB of these absorbers were almost greater than 6 GHz(covering the entire Ku-band)in the thickness range of 2.0–2.2 mm except the sample S-1.0-800.As far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss(RLmin)value was−25.8 dB.Moreover,in the far-field condition,the radar cross section(RCS)of S-0.8-700 can be reduced to 19.6 dB·m^(2).We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.展开更多
The properties of photodetectors based on two-dimensional materials can be significantly enhanced by avalanche effect.However,a high avalanche breakdown voltage is needed to reach impact ionization,which leads to high...The properties of photodetectors based on two-dimensional materials can be significantly enhanced by avalanche effect.However,a high avalanche breakdown voltage is needed to reach impact ionization,which leads to high power consumption.Here,we report the unique features of a low-voltage avalanche phototransistor formed by an in-plane WSe_(2)field effect transistor(FET)with an out-of-plane WSe_(2)/WS_(2)P–N heterojunction(HJ FET).The avalanche breakdown voltage in the device can be decreased from−31 to−8.5 V when compared with that in WSe_(2)FET.The inherent mechanism is mainly related to the redistributed electric field in the WSe_(2)channel after the formation of the out-of-plane P–N heterojunction.When the bias voltage is−16.5 V,the photoresponsivity in the HJ FET is enhanced from 1.5 to 135 A/W,which is significantly higher than that in the WSe_(2)FET because of the obvious reduction of the avalanche breakdown voltage.Moreover,HJ FET shows a higher responsivity than WSe_(2)FET in the range of 400–1,100 nm under low bias voltage.This phenomenon is caused by accelerating electron–hole spatial separation in the heterojunction.These results indicate that the use of an WSe_(2)FET with an out-of-plane WSe_(2)/WS_(2)heterojunction is ideal for high-performance photodetectors with low power consumption.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51971111 and 52273247)the Fund of Prospective Layout of Scientific Research for NUAA(Nanjing University of Aeronautics and Astronautics)(No.ILA220461A22).
文摘Heterogeneous interface engineering strategy is an effective method to optimize electromagnetic functional materials.However,the mechanism of heterogeneous interfaces on microwave absorption is still unclear.In this study,abundant heterointerfaces were customized in hierarchical structures via a collaborative strategy of lyophilization and hard templates.The impressive electromagnetic heterostructures and strong interfacial polarization were realized on the zero-dimensional(0D)hexagonal close-packed(hcp)-face-centered cubic(fcc)Co/two-dimensional(2D)Co(OH)_(2)nanosheets@three-dimensional(3D)porous carbon nanosheets(Co/Co(OH)_(2)@PCN).By controlling the carbonization temperature,the electromagnetic parameters were further adjusted to broaden the effective absorption bandwidth(EAB).Accordingly,the EAB of these absorbers were almost greater than 6 GHz(covering the entire Ku-band)in the thickness range of 2.0–2.2 mm except the sample S-1.0-800.As far as to the S-0.8-700 achieved an EAB up to 7.1 GHz at 2.2 mm and the minimum reflection loss(RLmin)value was−25.8 dB.Moreover,in the far-field condition,the radar cross section(RCS)of S-0.8-700 can be reduced to 19.6 dB·m^(2).We believe that this work will stimulate interest in interface engineering and provide a direction for achieving efficient absorbing materials.
基金supported by the National Key Research and Development Program of China(No.2019YFB2204400)Fundamental Research Funds for the Central Universities,the Innovation Fund of Xidian University,and the Natural Science Basic Research Program of Shaanxi(No.2022JQ-650).
文摘The properties of photodetectors based on two-dimensional materials can be significantly enhanced by avalanche effect.However,a high avalanche breakdown voltage is needed to reach impact ionization,which leads to high power consumption.Here,we report the unique features of a low-voltage avalanche phototransistor formed by an in-plane WSe_(2)field effect transistor(FET)with an out-of-plane WSe_(2)/WS_(2)P–N heterojunction(HJ FET).The avalanche breakdown voltage in the device can be decreased from−31 to−8.5 V when compared with that in WSe_(2)FET.The inherent mechanism is mainly related to the redistributed electric field in the WSe_(2)channel after the formation of the out-of-plane P–N heterojunction.When the bias voltage is−16.5 V,the photoresponsivity in the HJ FET is enhanced from 1.5 to 135 A/W,which is significantly higher than that in the WSe_(2)FET because of the obvious reduction of the avalanche breakdown voltage.Moreover,HJ FET shows a higher responsivity than WSe_(2)FET in the range of 400–1,100 nm under low bias voltage.This phenomenon is caused by accelerating electron–hole spatial separation in the heterojunction.These results indicate that the use of an WSe_(2)FET with an out-of-plane WSe_(2)/WS_(2)heterojunction is ideal for high-performance photodetectors with low power consumption.
