In_(2/3)PSe_(3)因其对称性破缺的晶体结构、良好的发光性质和直接带隙特性,在光电子器件领域具有巨大的应用潜力.本研究采用化学气相输运法合成了In_(2/3)PSe_(3)单晶并通过机械剥离方法获得了二维In_(2/3)PSe_(3)纳米片.借助二次谐波(...In_(2/3)PSe_(3)因其对称性破缺的晶体结构、良好的发光性质和直接带隙特性,在光电子器件领域具有巨大的应用潜力.本研究采用化学气相输运法合成了In_(2/3)PSe_(3)单晶并通过机械剥离方法获得了二维In_(2/3)PSe_(3)纳米片.借助二次谐波(second-harmonic generation,SHG)和光致发光(photoluminescence,PL)光谱对其非线性光学和发光性质进行了系统的研究,结果表明In_(2/3)PSe_(3)纳米片具有本征对称性破缺的晶体结构和优异的发光性质.通过微纳加工技术构筑了基于In_(2/3)PSe_(3)纳米片的光探测器并研究了其光探测性能.基于In_(2/3)PSe_(3)纳米片的光探测器在365 nm波长的光照下,具有极低的暗电流(25 f A)、优异的探测度(6.28×10^(11)Jones)、高的开关比(4×10^(4))以及超快的响应速度(14μs/24μs).这些优异的光电性能预示着In_(2/3)PSe_(3)有潜力成为新一代高性能光探测器的核心材料.展开更多
通过合金化改性技术,Ge可由间接带隙半导体转变为直接带隙半导体.改性后的Ge半导体可同时应用于光子器件和电子器件,极具发展潜力.基于直接带隙Ge1-x Sn x半导体合金8带Kronig-Penny模型,重点研究了其导带有效状态密度、价带有效状态密...通过合金化改性技术,Ge可由间接带隙半导体转变为直接带隙半导体.改性后的Ge半导体可同时应用于光子器件和电子器件,极具发展潜力.基于直接带隙Ge1-x Sn x半导体合金8带Kronig-Penny模型,重点研究了其导带有效状态密度、价带有效状态密度及本征载流子浓度,旨在为直接带隙改性Ge半导体物理的理解及相关器件的研究设计提供有价值的参考.研究结果表明:直接带隙Ge1-x Sn x合金导带有效状态密度随着Sn组分x的增加而明显减小,价带有效状态密度几乎不随Sn组分变化.与体Ge半导体相比,直接带隙Ge1-x Sn x合金导带有效状态密度、价带有效状态密度分别低两个和一个数量级;直接带隙Ge1-x Sn x合金本征载流子浓度随着Sn组分的增加而增加,比体Ge半导体高一个数量级以上.展开更多
Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature,...Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature, a layered ferromagnetic semiconductor with high Curie temperature(Tc) is yet to be unveiled. Here, we theoretically predicted a family of high Tcferromagnetic monolayers, namely MnNX and CrCX(X = Cl, Br and I; C = S, Se and Te). Their Tcvalues were predicted from over 100 K to near 500 K with Monte Carlo simulations using an anisotropic Heisenberg model. Eight members among them show semiconducting bandgaps varying from roughly 0.23 to 1.85 eV. These semiconducting monolayers also show extremely large anisotropy, i.e. ～10~1 for effective masses and ～10~2 for carrier mobilities, along the two in-plane lattice directions of these layers. Additional orbital anisotropy leads to a spin-locked linear dichroism, in different from previously known circular and linear dichroisms in layered materials.Together with the mobility anisotropy, it offers a spin-, dichroism-and mobility-anisotropy locking.These results manifest the potential of this 2D family for both fundamental research and high performance spin-dependent electronic and optoelectronic devices.展开更多
文摘In_(2/3)PSe_(3)因其对称性破缺的晶体结构、良好的发光性质和直接带隙特性,在光电子器件领域具有巨大的应用潜力.本研究采用化学气相输运法合成了In_(2/3)PSe_(3)单晶并通过机械剥离方法获得了二维In_(2/3)PSe_(3)纳米片.借助二次谐波(second-harmonic generation,SHG)和光致发光(photoluminescence,PL)光谱对其非线性光学和发光性质进行了系统的研究,结果表明In_(2/3)PSe_(3)纳米片具有本征对称性破缺的晶体结构和优异的发光性质.通过微纳加工技术构筑了基于In_(2/3)PSe_(3)纳米片的光探测器并研究了其光探测性能.基于In_(2/3)PSe_(3)纳米片的光探测器在365 nm波长的光照下,具有极低的暗电流(25 f A)、优异的探测度(6.28×10^(11)Jones)、高的开关比(4×10^(4))以及超快的响应速度(14μs/24μs).这些优异的光电性能预示着In_(2/3)PSe_(3)有潜力成为新一代高性能光探测器的核心材料.
文摘通过合金化改性技术,Ge可由间接带隙半导体转变为直接带隙半导体.改性后的Ge半导体可同时应用于光子器件和电子器件,极具发展潜力.基于直接带隙Ge1-x Sn x半导体合金8带Kronig-Penny模型,重点研究了其导带有效状态密度、价带有效状态密度及本征载流子浓度,旨在为直接带隙改性Ge半导体物理的理解及相关器件的研究设计提供有价值的参考.研究结果表明:直接带隙Ge1-x Sn x合金导带有效状态密度随着Sn组分x的增加而明显减小,价带有效状态密度几乎不随Sn组分变化.与体Ge半导体相比,直接带隙Ge1-x Sn x合金导带有效状态密度、价带有效状态密度分别低两个和一个数量级;直接带隙Ge1-x Sn x合金本征载流子浓度随着Sn组分的增加而增加,比体Ge半导体高一个数量级以上.
基金supported by the National Natural Science Foundation of China(11274380,91433103,11622437 and 61674171)the Fundamental Research Funds for the Central Universities of China+2 种基金the Research Funds of Renmin University of China(16XNLQ01)the Strategic Priority Research Program of Chinese Academy of Sciences(XDB30000000)supported by the Outstanding Innovative Talents Cultivation Funded Programs 2017 of Renmin University of China
文摘Two-dimensional magnets have received increasing attention since Cr_2Ge_2Te_6 and CrI_3 were experimentally exfoliated and measured in 2017. Although layered ferromagnetic metals were demonstrated at room temperature, a layered ferromagnetic semiconductor with high Curie temperature(Tc) is yet to be unveiled. Here, we theoretically predicted a family of high Tcferromagnetic monolayers, namely MnNX and CrCX(X = Cl, Br and I; C = S, Se and Te). Their Tcvalues were predicted from over 100 K to near 500 K with Monte Carlo simulations using an anisotropic Heisenberg model. Eight members among them show semiconducting bandgaps varying from roughly 0.23 to 1.85 eV. These semiconducting monolayers also show extremely large anisotropy, i.e. ～10~1 for effective masses and ～10~2 for carrier mobilities, along the two in-plane lattice directions of these layers. Additional orbital anisotropy leads to a spin-locked linear dichroism, in different from previously known circular and linear dichroisms in layered materials.Together with the mobility anisotropy, it offers a spin-, dichroism-and mobility-anisotropy locking.These results manifest the potential of this 2D family for both fundamental research and high performance spin-dependent electronic and optoelectronic devices.
