近年来二维材料因其超薄的厚度及新颖的电、光及光电特性受到了广泛关注.此外,二维材料表面无悬挂键,这使得其可以直接通过范德华力相互结合形成范德华异质结,为构建具有优异性能的新型器件提供了新的机遇.本文采用范德华集成方法将n型...近年来二维材料因其超薄的厚度及新颖的电、光及光电特性受到了广泛关注.此外,二维材料表面无悬挂键,这使得其可以直接通过范德华力相互结合形成范德华异质结,为构建具有优异性能的新型器件提供了新的机遇.本文采用范德华集成方法将n型硫化镉和p型黑磷垂直堆垛起来构筑了p-n结二极管.输运特性测试表明,该p-n结器件表现出高的整流比(8×103)和低的理想因子(1.5).同时,在光照下器件表现出超高的光响应度和比探测率,分别可达9.2×105A W-1和3.2×1013Jones,与目前所报道的二维异质结光电探测的最高水平相当.当器件工作于自驱动探测模式时,仍表现出极好的光探测性能,光响应度和响应速度分别可达0.27 A W-1和~10 ms.所制备的硫化镉/黑磷异质结器件将会在新一代纳米电子、光电子器件中扮演重要角色.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted extensive attention due to their unique electronic and optical properties.In particular,TMDs can be fexibly combined to form diverse vertical van...Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted extensive attention due to their unique electronic and optical properties.In particular,TMDs can be fexibly combined to form diverse vertical van der Waals(vdWs)heterostructures without the limitation of lattice matching,which creates vast opportunities for fundamental investigation of novel optoelectronic applications.Here,we report an atomically thin vertical p-n junction WSe_(2)/MoS_(2)produced by a chemical vapor deposition method.Transmission electron microscopy and steady-state photoluminescence experiments reveal its high quality and excellent optical properties.Back gate feld efect transistor(FET)constructed using this p-n junction exhibits bipolar behaviors and a mobility of 9 cm^(2)/(V·s).In addition,the photodetector based on MoS_(2)/WSe_(2)heterostructures displays outstanding optoelectronic properties(R=8 A/W,D^(*)=2.93×10^(11)Jones,on/of ratio of 10^(4)),which benefted from the built-in electric feld across the interface.The direct growth of TMDs p-n vertical heterostructures may ofer a novel platform for future optoelectronic applications.展开更多
Understanding the fundamental charge carrier dynamics is of great significance for photodetectors with both high speed and high responsivity.Devices based on two-dimensional(2D)transition metal dichalcogenides can exh...Understanding the fundamental charge carrier dynamics is of great significance for photodetectors with both high speed and high responsivity.Devices based on two-dimensional(2D)transition metal dichalcogenides can exhibit picosecond photoresponse speed.However,2D materials naturally have low absorption,and when increasing thickness to gain higher responsivity,the response time usually slows to nanoseconds,limiting their photodetection performance.Here,by taking time-resolved photocurrent measurements,we demonstrated that graphene/MoTe_(2) van der Waals heterojunctions realize a fast 10 ps photoresponse time owing to the reduced average photocurrent drift time in the heterojunction,which is fundamentally distinct from traditional Dirac semimetal photodetectors such as graphene or Cd_(3)As_(2) and implies a photodetection bandwidth as wide as 100 GHz.Furthermore,we found that an additional charge carrier transport channel provided by graphene can ef-fectively decrease the photocurrent recombination loss to the entire device,preserving a high responsivity in the near-infrared region.Our study provides a deeper understanding of the ultrafast electrical response in van der Waals heterojunctions and offers a promising approach for the realization of photodetectors with both high responsivity and ultrafast electrical response.展开更多
基金supported by the National Natural Science Foundation of China(U19A2090,51902098,51972105,51525202 and 61574054)Hunan Provincial Natural Science Foundation of China(2018RS3051)。
文摘近年来二维材料因其超薄的厚度及新颖的电、光及光电特性受到了广泛关注.此外,二维材料表面无悬挂键,这使得其可以直接通过范德华力相互结合形成范德华异质结,为构建具有优异性能的新型器件提供了新的机遇.本文采用范德华集成方法将n型硫化镉和p型黑磷垂直堆垛起来构筑了p-n结二极管.输运特性测试表明,该p-n结器件表现出高的整流比(8×103)和低的理想因子(1.5).同时,在光照下器件表现出超高的光响应度和比探测率,分别可达9.2×105A W-1和3.2×1013Jones,与目前所报道的二维异质结光电探测的最高水平相当.当器件工作于自驱动探测模式时,仍表现出极好的光探测性能,光响应度和响应速度分别可达0.27 A W-1和~10 ms.所制备的硫化镉/黑磷异质结器件将会在新一代纳米电子、光电子器件中扮演重要角色.
基金supported by the National Natural Science Foundation of China (U19A2090, 51902098, 51972105, 51525202, and 61574054)the Hunan Provincial Natural Science Foundation (2018RS3051)。
基金the National Natural Science Foundation of China(Grant Nos.62090035,U19A2090,and 61905071)the Key Program of the Hunan Provincial Science and Technology Department(Nos.2019XK2001 and 2020XK2001)the International Science and Technology Innovation Cooperation Base of Hunan Province(No.2018WK4004).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)have attracted extensive attention due to their unique electronic and optical properties.In particular,TMDs can be fexibly combined to form diverse vertical van der Waals(vdWs)heterostructures without the limitation of lattice matching,which creates vast opportunities for fundamental investigation of novel optoelectronic applications.Here,we report an atomically thin vertical p-n junction WSe_(2)/MoS_(2)produced by a chemical vapor deposition method.Transmission electron microscopy and steady-state photoluminescence experiments reveal its high quality and excellent optical properties.Back gate feld efect transistor(FET)constructed using this p-n junction exhibits bipolar behaviors and a mobility of 9 cm^(2)/(V·s).In addition,the photodetector based on MoS_(2)/WSe_(2)heterostructures displays outstanding optoelectronic properties(R=8 A/W,D^(*)=2.93×10^(11)Jones,on/of ratio of 10^(4)),which benefted from the built-in electric feld across the interface.The direct growth of TMDs p-n vertical heterostructures may ofer a novel platform for future optoelectronic applications.
基金This work was supported by the National Natural Science Foundation of China(Grants No.52022029,91850116,51772084,and U19A2090)the Sino-German Center for Research Promotion(Grant No.GZ1390)the Hunan Provincial Natural Science Foundation of China(Grants No.2018RS3051 and 2019XK2001)。
文摘Understanding the fundamental charge carrier dynamics is of great significance for photodetectors with both high speed and high responsivity.Devices based on two-dimensional(2D)transition metal dichalcogenides can exhibit picosecond photoresponse speed.However,2D materials naturally have low absorption,and when increasing thickness to gain higher responsivity,the response time usually slows to nanoseconds,limiting their photodetection performance.Here,by taking time-resolved photocurrent measurements,we demonstrated that graphene/MoTe_(2) van der Waals heterojunctions realize a fast 10 ps photoresponse time owing to the reduced average photocurrent drift time in the heterojunction,which is fundamentally distinct from traditional Dirac semimetal photodetectors such as graphene or Cd_(3)As_(2) and implies a photodetection bandwidth as wide as 100 GHz.Furthermore,we found that an additional charge carrier transport channel provided by graphene can ef-fectively decrease the photocurrent recombination loss to the entire device,preserving a high responsivity in the near-infrared region.Our study provides a deeper understanding of the ultrafast electrical response in van der Waals heterojunctions and offers a promising approach for the realization of photodetectors with both high responsivity and ultrafast electrical response.
