Two-dimensional(2D)semiconductors have attracted considerable interest for their unique physical properties.Here,we report the intrinsic cryogenic electronic transport properties in few-layer MoSe_(2)field-effect tran...Two-dimensional(2D)semiconductors have attracted considerable interest for their unique physical properties.Here,we report the intrinsic cryogenic electronic transport properties in few-layer MoSe_(2)field-effect transistors(FETs)that are fully encapsulated in ultraclean hexagonal boron nitride dielectrics and are simultaneously van der Waals contacted with gold electrodes.The FETs exhibit electronically favorable channel/dielectric interfaces with low densities of interfacial traps(<1010cm^(-2)),which lead to outstanding device characteristics at room temperature,including near-Boltzmann-limit subthreshold swings(65 mV/dec),high carrier mobilities(53–68 cm^(2)·V-1·s^(-1)),and negligible scanning hystereses(<15 mV).The dependence of various contact-related parameters with temperature and carrier density is also systematically characterized to understand the van der Waals contacts between gold and MoSe_(2).The results provide insightful information about the device physics in van der Waals contacted and encapsulated 2D FETs.展开更多
Two-dimensional(2D)van der Waals semiconductors are appealing for low-power transistors.Here,we show the feasibility in enhancing carrier mobility in 2D semiconductors through engineering the vertical distribution of ...Two-dimensional(2D)van der Waals semiconductors are appealing for low-power transistors.Here,we show the feasibility in enhancing carrier mobility in 2D semiconductors through engineering the vertical distribution of carriers confined inside ultrathin channels via symmetrizing gate configuration or increasing channel thickness.Through self-consistently solving the Schr¨odinger–Poisson equations,the shapes of electron envelope functions are extensively investigated by clarifying their relationship with gate configuration,channel thickness,dielectric permittivity,and electron density.The impacts of electron distribution variation on various carrier scattering matrix elements and overall carrier mobility are insightfully clarified.It is found that the carrier mobility can be generally enhanced in the dual-gated configuration due to the centralization of carrier redistribution in the nanometer-thick semiconductor channels and the rate of increase reaches up to 23%in Hf O2 dual-gated 10-layer MoS_(2) channels.This finding represents a viable strategy for performance optimization in transistors consisting of 2D semiconductors.展开更多
Epitaxial La2/3Cal/3MnO3 thin films grown on LaA103 （001） substrates were irradiated with low-energy 120-keV H＋ ions over doses ranging from 1012 ions/cm2 to 1017 ions/cm2. The irradiation suppresses the intrinsic ...Epitaxial La2/3Cal/3MnO3 thin films grown on LaA103 （001） substrates were irradiated with low-energy 120-keV H＋ ions over doses ranging from 1012 ions/cm2 to 1017 ions/cm2. The irradiation suppresses the intrinsic insulator-metal （I-M） transition temperature and increases the resistance by reducing the crystallographic symmetry of the films. No irradiation-induced columnar defects were observed in any of the samples. The specific film irradiated at a critical dose around 8 x 1015 ions/cm2 is in a threshold state of the electric insulator where the I-M transition is absent. In an external field of 4 T or higher, the I-M transition is restored and thus an enormous magnetoresistance is observed, while a negative temperature coefficient resumes as the temperature is reduced further. Magnetic relaxation behavior is confirmed in this and other heavily irradiated samples. The results are interpreted in terms of the displacement of oxygen atoms provoked by ion irradiation and the resulting magnetic glassy state, which can be driven into a phase coexistence of metallic ferromagnetic droplets and the insulating glass matrix in a magnetic field.展开更多
基金the National Key R&D Program of China(Grant Nos.2022YFA1203802 and 2021YFA1202903)the National Natural Science Foundation of China(Grant Nos.92264202,61974060,and 61674080)the Innovation and Entrepreneurship Program of Jiangsu Province。
文摘Two-dimensional(2D)semiconductors have attracted considerable interest for their unique physical properties.Here,we report the intrinsic cryogenic electronic transport properties in few-layer MoSe_(2)field-effect transistors(FETs)that are fully encapsulated in ultraclean hexagonal boron nitride dielectrics and are simultaneously van der Waals contacted with gold electrodes.The FETs exhibit electronically favorable channel/dielectric interfaces with low densities of interfacial traps(<1010cm^(-2)),which lead to outstanding device characteristics at room temperature,including near-Boltzmann-limit subthreshold swings(65 mV/dec),high carrier mobilities(53–68 cm^(2)·V-1·s^(-1)),and negligible scanning hystereses(<15 mV).The dependence of various contact-related parameters with temperature and carrier density is also systematically characterized to understand the van der Waals contacts between gold and MoSe_(2).The results provide insightful information about the device physics in van der Waals contacted and encapsulated 2D FETs.
基金the National Key R&D Program of China(Grant Nos.2022YFA1203802 and 2021YFA1202903)the National Natural Science Foundation of China(Grant Nos.92264202,61974060,and 61674080)the Innovation and Entrepreneurship Program of Jiangsu Province。
文摘Two-dimensional(2D)van der Waals semiconductors are appealing for low-power transistors.Here,we show the feasibility in enhancing carrier mobility in 2D semiconductors through engineering the vertical distribution of carriers confined inside ultrathin channels via symmetrizing gate configuration or increasing channel thickness.Through self-consistently solving the Schr¨odinger–Poisson equations,the shapes of electron envelope functions are extensively investigated by clarifying their relationship with gate configuration,channel thickness,dielectric permittivity,and electron density.The impacts of electron distribution variation on various carrier scattering matrix elements and overall carrier mobility are insightfully clarified.It is found that the carrier mobility can be generally enhanced in the dual-gated configuration due to the centralization of carrier redistribution in the nanometer-thick semiconductor channels and the rate of increase reaches up to 23%in Hf O2 dual-gated 10-layer MoS_(2) channels.This finding represents a viable strategy for performance optimization in transistors consisting of 2D semiconductors.
基金Supported by the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No KJCX2-SW-W26, and the National Natural Science Foundation of China under Grant Nos 90406017 and 10427402.
文摘Metal-tip/Pr0.7Ca0.3MnO3/Pt 设备拥有二种类型我 V 磁滞现象：顺时针方向顺时针方向对相反取决于尖端材料。为设备的这二种类型的分类的标准能简单地基于是否为金属尖端的氧化的免费精力是的吉布斯比 PCMO 的更低或高分别地。当时顺时针方向，磁滞现象能被归因于电场导致的氧化 / 减小，柜台顺时针方向，磁滞现象能被氧空缺移植在一个电场解释。交替水流的传导力系列也以高抵抗的状态揭示在设备的这二个范畴之间的不同跳跃障碍。
基金supported by the National Basic Research Program of China(Grant No.2011CBA00106)the National Natural Science Foundation of China(GrantNos.11174342,11161130519,and 11104333)
文摘Epitaxial La2/3Cal/3MnO3 thin films grown on LaA103 （001） substrates were irradiated with low-energy 120-keV H＋ ions over doses ranging from 1012 ions/cm2 to 1017 ions/cm2. The irradiation suppresses the intrinsic insulator-metal （I-M） transition temperature and increases the resistance by reducing the crystallographic symmetry of the films. No irradiation-induced columnar defects were observed in any of the samples. The specific film irradiated at a critical dose around 8 x 1015 ions/cm2 is in a threshold state of the electric insulator where the I-M transition is absent. In an external field of 4 T or higher, the I-M transition is restored and thus an enormous magnetoresistance is observed, while a negative temperature coefficient resumes as the temperature is reduced further. Magnetic relaxation behavior is confirmed in this and other heavily irradiated samples. The results are interpreted in terms of the displacement of oxygen atoms provoked by ion irradiation and the resulting magnetic glassy state, which can be driven into a phase coexistence of metallic ferromagnetic droplets and the insulating glass matrix in a magnetic field.
