Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so fa...Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS polycrystals.This work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier mobility.As a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S sample.Interestingly,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS sample.Moreover,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.展开更多
To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular ti...To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular tin-based contamination consisting of micro-and macroparticles was deposited on silicon via physical vapor deposition(PVD).The electrodedriven hydrogen plasma at different power levels was systematically diagnosed using a Langmuir probe and a retarding field ion energy analyzer(RFEA).Moreover,the magnitude of the self-biasing voltage was measured at different power levels,and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage(E_(RFEA)-eV_(self)).XPS analysis of O 1s and Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning.Analysis of surface and cross-section morphology revealed that holes emerged on the upper part of the macroparticles while its bottom remained smooth.Hills and folds appeared on the upper part of the microparticles,confirming the top-down cleaning mode with hydrogen plasma.This study provides an in situ electrode-driven hydrogen plasma etching process for tin-based contamination and will provide meaningful guidance for understanding the chemical mechanism of reduction and etching.展开更多
Negative permittivity has been widely studied in various metamaterials and percolating composites, of which the anomalous dielectric behavior was attributed to critical structural properties of building blocks.Herein,...Negative permittivity has been widely studied in various metamaterials and percolating composites, of which the anomalous dielectric behavior was attributed to critical structural properties of building blocks.Herein, mono-phase ceramics of indium tin oxides(ITO) were sintered for epsilon-negative materials in MHz-k Hz frequency regions. Electrical conductivity and complex permittivity were analyzed with DrudeLorentz oscillator model. Carriers’ characters were measured based on Hall effect and the magnitude and frequency dispersion of negative permittivity were mainly determined by carrier concentration.Temperature-dependent dielectric properties further proved the epsilon-negative behaviors were closely associated with free carriers’ collective responses. It’s found that negative permittivity of ITO ceramics was mainly caused by plasma oscillations of free carriers, while the dielectric loss was mainly attributed to conduction loss. Negative permittivity realized here was related to materials intrinsic nature and this work preliminarily determined the mechanism of negative permittivity in doped ceramics from the perspective of carriers.展开更多
Extreme ultraviolet lithography is most promising for the next generation lithography. However, debris from laser-produced plasma, particularly energetic ions, severely decreases the lifetime of extreme ultraviolet op...Extreme ultraviolet lithography is most promising for the next generation lithography. However, debris from laser-produced plasma, particularly energetic ions, severely decreases the lifetime of extreme ultraviolet optics. We measured the characteris- tics of ions from tin plasma by the time of flight method with a frequency-doubled Nd： YAG laser at the intensity of 3.5x1010 W/cm2 （532 nm, 8 ns）. Our measurement shows that the maximum and peak of tin ions energies from plasma under the above experimental parameters are about 4.2 and 1.8 keV, respectively. Moreover, it is found that kinetic energy angular distribution of tin ions can be fitted by cos0.8（θ）, where θ is the angle with respect to the target normal. We also investigated the mitigation effect of argon, helium gases to the tin ions, and found that tin ions from the plasma can be mitigated effectively at the pressure -38 mTorr for argon or -375 mTorr for helium, respectively.展开更多
基金supported by the Basic Science Center Project of Natural Science Foundation of China(51788104)the National Key R&D Program of China(2018YFB0703603).
文摘Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS polycrystals.This work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier mobility.As a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S sample.Interestingly,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS sample.Moreover,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.
基金funded by the Institutional Research Fund from Sichuan University(No.2020SCUNL211)。
文摘To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular tin-based contamination consisting of micro-and macroparticles was deposited on silicon via physical vapor deposition(PVD).The electrodedriven hydrogen plasma at different power levels was systematically diagnosed using a Langmuir probe and a retarding field ion energy analyzer(RFEA).Moreover,the magnitude of the self-biasing voltage was measured at different power levels,and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage(E_(RFEA)-eV_(self)).XPS analysis of O 1s and Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning.Analysis of surface and cross-section morphology revealed that holes emerged on the upper part of the macroparticles while its bottom remained smooth.Hills and folds appeared on the upper part of the microparticles,confirming the top-down cleaning mode with hydrogen plasma.This study provides an in situ electrode-driven hydrogen plasma etching process for tin-based contamination and will provide meaningful guidance for understanding the chemical mechanism of reduction and etching.
基金supported by the National Natural Science Foundation of China(Nos.51771104,51871146,51971119)the Future Plan for Young Talent of Shandong University(No.2016WLJH40)the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-10-E00053)。
文摘Negative permittivity has been widely studied in various metamaterials and percolating composites, of which the anomalous dielectric behavior was attributed to critical structural properties of building blocks.Herein, mono-phase ceramics of indium tin oxides(ITO) were sintered for epsilon-negative materials in MHz-k Hz frequency regions. Electrical conductivity and complex permittivity were analyzed with DrudeLorentz oscillator model. Carriers’ characters were measured based on Hall effect and the magnitude and frequency dispersion of negative permittivity were mainly determined by carrier concentration.Temperature-dependent dielectric properties further proved the epsilon-negative behaviors were closely associated with free carriers’ collective responses. It’s found that negative permittivity of ITO ceramics was mainly caused by plasma oscillations of free carriers, while the dielectric loss was mainly attributed to conduction loss. Negative permittivity realized here was related to materials intrinsic nature and this work preliminarily determined the mechanism of negative permittivity in doped ceramics from the perspective of carriers.
基金supported by the National Natural Science Foundation ofChina (Grant Nos. 60978014,61178022 and 11074027)the Basic Research Fund from Sci. & Tech. Department of Jilin Province (Grant Nos.20100521,20100168 and 20111812)
文摘Extreme ultraviolet lithography is most promising for the next generation lithography. However, debris from laser-produced plasma, particularly energetic ions, severely decreases the lifetime of extreme ultraviolet optics. We measured the characteris- tics of ions from tin plasma by the time of flight method with a frequency-doubled Nd： YAG laser at the intensity of 3.5x1010 W/cm2 （532 nm, 8 ns）. Our measurement shows that the maximum and peak of tin ions energies from plasma under the above experimental parameters are about 4.2 and 1.8 keV, respectively. Moreover, it is found that kinetic energy angular distribution of tin ions can be fitted by cos0.8（θ）, where θ is the angle with respect to the target normal. We also investigated the mitigation effect of argon, helium gases to the tin ions, and found that tin ions from the plasma can be mitigated effectively at the pressure -38 mTorr for argon or -375 mTorr for helium, respectively.
