The gradient-doping structure is first applied to prepare the transmission-mode GaAs photocathode and the integral sensitivity of the sealed image tube achieves 1420μA/lm. This paper studies the inner carrier concent...The gradient-doping structure is first applied to prepare the transmission-mode GaAs photocathode and the integral sensitivity of the sealed image tube achieves 1420μA/lm. This paper studies the inner carrier concentration distribution of the gradient-doping transmission-mode GaAs photocathode after molecular beam epitaxy （MBE） growth using the electrochemical capacitance-voltage profiling. The results show that an ideal gradient-doping structure can be obtained by using MBE growth. The total band-bending energy in the gradient-doping GaAs active-layer with doping concentration ranging from 1×10^19 cm-3 to 1×1018 cm-3 is calculated to be 46.3 meV, which helps to improve the photoexcited electrons movement toward surface for the thin epilayer. In addition,by analysis of the band offsets, it is found that the worse carrier concentration discrepancy between GaAs and GaA1As causes a lower back interface electron potential barrier which decreases the amount of high-energy photoelectrons and affects the short-wave response.展开更多
We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have...We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have identified intriguing extra bump/dip features from anomalous Hall experiments on the films with thicknesses less than 12 nm. This observed Hall anomaly is phenomenologically consistent with the occurrence of a topological Hall effect （THE） in chiral magnets with a skyrmion phase. Furthermore, the THE contribution can be tuned by the film thickness, showing the key contribution of asymmetric interfaces in stabilizing N6el-type skyrmions. Our work demonstrates that a CrTe thin film on SrTiO3（111） substrates is a good material candidate for studying real-space topological transport.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos 60678043 and 60801036)
文摘The gradient-doping structure is first applied to prepare the transmission-mode GaAs photocathode and the integral sensitivity of the sealed image tube achieves 1420μA/lm. This paper studies the inner carrier concentration distribution of the gradient-doping transmission-mode GaAs photocathode after molecular beam epitaxy （MBE） growth using the electrochemical capacitance-voltage profiling. The results show that an ideal gradient-doping structure can be obtained by using MBE growth. The total band-bending energy in the gradient-doping GaAs active-layer with doping concentration ranging from 1×10^19 cm-3 to 1×1018 cm-3 is calculated to be 46.3 meV, which helps to improve the photoexcited electrons movement toward surface for the thin epilayer. In addition,by analysis of the band offsets, it is found that the worse carrier concentration discrepancy between GaAs and GaA1As causes a lower back interface electron potential barrier which decreases the amount of high-energy photoelectrons and affects the short-wave response.
文摘We have studied the magnetic and electrical transport properties of epitaxial NiAs-type CrTe thin films grown on SrTiO3（111） substrates. Unlike rectangle hysteresis loops obtained from magnetic measurements, we have identified intriguing extra bump/dip features from anomalous Hall experiments on the films with thicknesses less than 12 nm. This observed Hall anomaly is phenomenologically consistent with the occurrence of a topological Hall effect （THE） in chiral magnets with a skyrmion phase. Furthermore, the THE contribution can be tuned by the film thickness, showing the key contribution of asymmetric interfaces in stabilizing N6el-type skyrmions. Our work demonstrates that a CrTe thin film on SrTiO3（111） substrates is a good material candidate for studying real-space topological transport.
