We measure the time-resolved terahertz spectroscopy of GeSn thin film and studied the ultrafast dynamics of its photo-generated carriers.The experimental results show that there are photo-generated carriers in GeSn un...We measure the time-resolved terahertz spectroscopy of GeSn thin film and studied the ultrafast dynamics of its photo-generated carriers.The experimental results show that there are photo-generated carriers in GeSn under femtosecond laser excitation at 2500 nm,and its pump-induced photoconductivity can be explained by the Drude–Smith model.The carrier recombination process is mainly dominated by defect-assisted Auger processes and defect capture.The firstand second-order recombination rates are obtained by the rate equation fitting,which are(2.6±1.1)×10^(-2)ps^(-1)and(6.6±1.8)×10^(-19)cm^(3)·ps^(-1),respectively.Meanwhile,we also obtain the diffusion length of photo-generated carriers in GeSn,which is about 0.4μm,and it changes with the pump delay time.These results are important for the GeSn-based infrared optoelectronic devices,and demonstrate that Ge Sn materials can be applied to high-speed optoelectronic detectors and other applications.展开更多
Iron(Fe)is an essential micronutrient for all organisms.Fe availability in the soil is usually much lower than that required for plant growth,and Fe deficiencies seriously restrict crop growth and yield.Calcium(Ca2+)i...Iron(Fe)is an essential micronutrient for all organisms.Fe availability in the soil is usually much lower than that required for plant growth,and Fe deficiencies seriously restrict crop growth and yield.Calcium(Ca2+)is a second messenger in all eukaryotes;however,it remains largely unknown how Ca2+regulates Fe deficiency.In this study,mutations in CPK21 and CPK23,which are two highly homologous calcium-dependent protein kinases,conferredimpaired growth and rootdevelopment under Fe-deficient conditions,whereas constitutively active CPK21 and CPK23 enhanced plant tolerance to Fe-deficient conditions.Furthermore,we found that CPK21 and CPK23 interacted with and phosphorylated the Fe transporter IRONREGULATED TRANSPORTER1(IRT1)at the Ser149 residue.Biochemical analyses and complementation of Fe transport in yeast and plants indicated that IRT1 Ser149 is critical for IRT1 transport activity.Taken together,these findings suggest that the CPK21/23-IRT1 signaling pathway is critical for Fe homeostasis in plants and provides targets for improving Fe-deficient environments and breeding crops resistant to Fe-deficient conditions.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12004067,11974070,62027807,and 52272137)the National Key R&D Program of China(Grant No.2022YFA1403000)。
文摘We measure the time-resolved terahertz spectroscopy of GeSn thin film and studied the ultrafast dynamics of its photo-generated carriers.The experimental results show that there are photo-generated carriers in GeSn under femtosecond laser excitation at 2500 nm,and its pump-induced photoconductivity can be explained by the Drude–Smith model.The carrier recombination process is mainly dominated by defect-assisted Auger processes and defect capture.The firstand second-order recombination rates are obtained by the rate equation fitting,which are(2.6±1.1)×10^(-2)ps^(-1)and(6.6±1.8)×10^(-19)cm^(3)·ps^(-1),respectively.Meanwhile,we also obtain the diffusion length of photo-generated carriers in GeSn,which is about 0.4μm,and it changes with the pump delay time.These results are important for the GeSn-based infrared optoelectronic devices,and demonstrate that Ge Sn materials can be applied to high-speed optoelectronic detectors and other applications.
基金supported by the National Natural Science Foundation of China(32222008,32100215,31900236)Northwest A&F University(Z111021604)+1 种基金the open funds of China Postdoctoral Science Foundation(2018M643740)Natural Science Basic Research Plan in Shaanxi Province of China(2019JQ-150).
文摘Iron(Fe)is an essential micronutrient for all organisms.Fe availability in the soil is usually much lower than that required for plant growth,and Fe deficiencies seriously restrict crop growth and yield.Calcium(Ca2+)is a second messenger in all eukaryotes;however,it remains largely unknown how Ca2+regulates Fe deficiency.In this study,mutations in CPK21 and CPK23,which are two highly homologous calcium-dependent protein kinases,conferredimpaired growth and rootdevelopment under Fe-deficient conditions,whereas constitutively active CPK21 and CPK23 enhanced plant tolerance to Fe-deficient conditions.Furthermore,we found that CPK21 and CPK23 interacted with and phosphorylated the Fe transporter IRONREGULATED TRANSPORTER1(IRT1)at the Ser149 residue.Biochemical analyses and complementation of Fe transport in yeast and plants indicated that IRT1 Ser149 is critical for IRT1 transport activity.Taken together,these findings suggest that the CPK21/23-IRT1 signaling pathway is critical for Fe homeostasis in plants and provides targets for improving Fe-deficient environments and breeding crops resistant to Fe-deficient conditions.
