Radio Frequency plasma enhanced Chemical Vapor Deposition (RF CVD) using N2, SiH4 and C2H4 as the reaction sources was used to prepare amorphous ternary Si x C y N z thin films. The chemical states of the C, Si and N...Radio Frequency plasma enhanced Chemical Vapor Deposition (RF CVD) using N2, SiH4 and C2H4 as the reaction sources was used to prepare amorphous ternary Si x C y N z thin films. The chemical states of the C, Si and N atoms in the films were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The refractive indexn, extinction coefficientk and optical band gapE opt of the thin films were investigated by UV-visible spectrophotometer and spectroscopic ellipsometer. The results show that a complex chemical bonding network rather than a simple mixture of Si3N4, SiC, CN x and a-C etc., may exist in the ternary thin films. Then's of the films are within the range of 1. 90–2. 45, andE opt's of all samples are within the range of 2. 71–2. 86 eV.展开更多
In comparison to monolayer(1L),multilayer(ML)two-dimensional(2D)semiconducting transition metal dichalcogenides(TMDs)exhibit more application potential for electronic and optoelectronic devices due to their improved c...In comparison to monolayer(1L),multilayer(ML)two-dimensional(2D)semiconducting transition metal dichalcogenides(TMDs)exhibit more application potential for electronic and optoelectronic devices due to their improved current carrying capability,higher mobility,and broader spectral response.However,the investigation of devices based on wafer-scale ML-TMDs is still restricted by the synthesis of uniform and high-quality ML films.In this work,we propose a strategy of stacking MoS_(2) monolayers via a vacuum transfer method,by which one could obtain wafer-scale high-quality MoS_(2) films with the desired number of layers at will.The optical characteristics of these stacked ML-MoS_(2) films(>2L)indicate a weak interlayer coupling.The stacked MLMoS_(2) phototransistors show improved optoelectrical performances and a broader spectral response(approximately 300-1,000 nm)than that of 1L-MoS_(2).Additionally,the dual-gate ML-MoS_(2) transistors enable enhanced electrostatic control over the stacked ML-MoS_(2) channel,and the 3L and 4L thicknesses exhibit the optimal device performances according to the turning point of the current on/off ratio and the subthreshold swing.展开更多
基金the National Natural Science Foundation of China (19975 0 3 5 )
文摘Radio Frequency plasma enhanced Chemical Vapor Deposition (RF CVD) using N2, SiH4 and C2H4 as the reaction sources was used to prepare amorphous ternary Si x C y N z thin films. The chemical states of the C, Si and N atoms in the films were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The refractive indexn, extinction coefficientk and optical band gapE opt of the thin films were investigated by UV-visible spectrophotometer and spectroscopic ellipsometer. The results show that a complex chemical bonding network rather than a simple mixture of Si3N4, SiC, CN x and a-C etc., may exist in the ternary thin films. Then's of the films are within the range of 1. 90–2. 45, andE opt's of all samples are within the range of 2. 71–2. 86 eV.
基金supported by the National Key Research and Development Program of China(Nos.2021YFA1200500 and 2018YFA0703700)in part by the National Natural Science Foundation of China(No.61774042)+1 种基金the Innovation Program of Shanghai Municipal Education Commission(No.2021-01-07-00-07-E00077)Shanghai Municipal Science and Technology Commission(Nos.21DZ1100900 and 20ZR1403200).
文摘In comparison to monolayer(1L),multilayer(ML)two-dimensional(2D)semiconducting transition metal dichalcogenides(TMDs)exhibit more application potential for electronic and optoelectronic devices due to their improved current carrying capability,higher mobility,and broader spectral response.However,the investigation of devices based on wafer-scale ML-TMDs is still restricted by the synthesis of uniform and high-quality ML films.In this work,we propose a strategy of stacking MoS_(2) monolayers via a vacuum transfer method,by which one could obtain wafer-scale high-quality MoS_(2) films with the desired number of layers at will.The optical characteristics of these stacked ML-MoS_(2) films(>2L)indicate a weak interlayer coupling.The stacked MLMoS_(2) phototransistors show improved optoelectrical performances and a broader spectral response(approximately 300-1,000 nm)than that of 1L-MoS_(2).Additionally,the dual-gate ML-MoS_(2) transistors enable enhanced electrostatic control over the stacked ML-MoS_(2) channel,and the 3L and 4L thicknesses exhibit the optimal device performances according to the turning point of the current on/off ratio and the subthreshold swing.
