The deep-level defects of Cd Zn Te（CZT）crystals grown by the modified vertical Bridgman（MVB）method act as trapping centers or recombination centers in the band gap,which have significant effects on its electrical ...The deep-level defects of Cd Zn Te（CZT）crystals grown by the modified vertical Bridgman（MVB）method act as trapping centers or recombination centers in the band gap,which have significant effects on its electrical properties.The resistivity and electron mobility–lifetime product of high resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT1 and low resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT2 were tested respectively.Their deep-level defects were identified by thermally stimulated current（TSC）spectroscopy and thermoelectric effect spectroscopy（TEES）respectively.Then the trap-related parameters were characterized by the simultaneous multiple peak analysis（SIMPA）method.The deep donor level（EDD/dominating dark current was calculated by the relationship between dark current and temperature.The Fermi-level was characterized by current–voltage measurements of temperature dependence.The width of the band gap was characterized by ultraviolet-visible-infrared transmittance spectroscopy.The results show the traps concentration and capture cross section of CZT1 are lower than CZT2,so its electron mobility–lifetime product is greater than CZT2.The Fermi-level of CZT1 is closer to the middle gap than CZT2.The degree of Fermi-level pinned by EDDof CZT1 is larger than CZT2.It can be concluded that the resistivity of CZT crystals increases as the degree of Fermi-level pinned near the middle gap by the deep donor level enlarges.展开更多
大气压氮气和空气介质阻挡均匀放电属于Townsend放电,并且以一种反常的方式熄灭,即放电在气隙电压上升过程中熄灭。为了实验研究阻挡介质材料表面"浅位阱"(能级<1 e V)对大气压均匀放电的影响,探究"反常熄灭"现...大气压氮气和空气介质阻挡均匀放电属于Townsend放电,并且以一种反常的方式熄灭,即放电在气隙电压上升过程中熄灭。为了实验研究阻挡介质材料表面"浅位阱"(能级<1 e V)对大气压均匀放电的影响,探究"反常熄灭"现象的机理,研制了一套热刺激电流测量装置,可施加最高25 kV直流电压,电流测量精度达0.1 p A,具有良好的抗干扰能力和重复性。测量陶瓷和石英玻璃的热刺激电流曲线,发现2种材料表面均存在一定数量的"浅位阱"。陶瓷浅位阱能级0.37 e V,石英玻璃为0.63 e V,陶瓷浅位阱能级更低,更易被轰击成为种子电子;陶瓷陷阱电荷量315.3 n C,石英玻璃为20.7 n C,陶瓷表面浅位阱数量远远多于石英玻璃。这与陶瓷材料能够实现大气压均匀介质阻挡放电(dielectric barrier discharge,DBD)但石英玻璃只是细丝放电的实验现象一致。证实材料表面浅位阱能够为放电提供种子电子,且数量越多越有利于实现大气压均匀DBD。展开更多
基金supported by the National Natural Science Foundation of China(No.51502234)the Scientific Research Plan Projects of Shaanxi Provincial Department of Education of China(No.15JS040)
文摘The deep-level defects of Cd Zn Te（CZT）crystals grown by the modified vertical Bridgman（MVB）method act as trapping centers or recombination centers in the band gap,which have significant effects on its electrical properties.The resistivity and electron mobility–lifetime product of high resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT1 and low resistivity Cd（0.9）Zn（0.1）Te wafer marked CZT2 were tested respectively.Their deep-level defects were identified by thermally stimulated current（TSC）spectroscopy and thermoelectric effect spectroscopy（TEES）respectively.Then the trap-related parameters were characterized by the simultaneous multiple peak analysis（SIMPA）method.The deep donor level（EDD/dominating dark current was calculated by the relationship between dark current and temperature.The Fermi-level was characterized by current–voltage measurements of temperature dependence.The width of the band gap was characterized by ultraviolet-visible-infrared transmittance spectroscopy.The results show the traps concentration and capture cross section of CZT1 are lower than CZT2,so its electron mobility–lifetime product is greater than CZT2.The Fermi-level of CZT1 is closer to the middle gap than CZT2.The degree of Fermi-level pinned by EDDof CZT1 is larger than CZT2.It can be concluded that the resistivity of CZT crystals increases as the degree of Fermi-level pinned near the middle gap by the deep donor level enlarges.
文摘大气压氮气和空气介质阻挡均匀放电属于Townsend放电,并且以一种反常的方式熄灭,即放电在气隙电压上升过程中熄灭。为了实验研究阻挡介质材料表面"浅位阱"(能级<1 e V)对大气压均匀放电的影响,探究"反常熄灭"现象的机理,研制了一套热刺激电流测量装置,可施加最高25 kV直流电压,电流测量精度达0.1 p A,具有良好的抗干扰能力和重复性。测量陶瓷和石英玻璃的热刺激电流曲线,发现2种材料表面均存在一定数量的"浅位阱"。陶瓷浅位阱能级0.37 e V,石英玻璃为0.63 e V,陶瓷浅位阱能级更低,更易被轰击成为种子电子;陶瓷陷阱电荷量315.3 n C,石英玻璃为20.7 n C,陶瓷表面浅位阱数量远远多于石英玻璃。这与陶瓷材料能够实现大气压均匀介质阻挡放电(dielectric barrier discharge,DBD)但石英玻璃只是细丝放电的实验现象一致。证实材料表面浅位阱能够为放电提供种子电子,且数量越多越有利于实现大气压均匀DBD。
