CAJ | 학술논문

采用生长态高电阻 CdZnTe 晶体制备出平面电极探测器,室温下测试了其在脉冲 X射线作用下的诱导电流曲线.分析了脉冲电流的上升时间以及脉冲衰减过程,发现脉冲上升时间约为2 ns,且不受外加偏压影响,而脉冲衰减过程可分为3阶段.利用α粒子结合飞行时间技术研究了 CdZnTe 晶体的载流子传输特性,分析了结构缺陷的散射和俘获-佉俘获对载流子传输特性的影响.同时对比了不同厚度的 CdZnTe探测器在不同电压下对脉冲 X 射线的响应特性.结果表明,当外加电场强度增加时,诱导脉冲电流曲线的半峰宽呈指数衰减,但当探测器厚度大于0．2 mm 时,随着探测器厚度的增加变化不明显.可能是由于材料中结构缺陷的浓度增加,对载流子的俘获和散射作用加剧,严重影响了载流子的传输过程和复合时间.
채용생장태고전조 CdZnTe 정체제비출평면전겁탐측기,실온하측시료기재맥충 X사선작용하적유도전류곡선.분석료맥충전류적상승시간이급맥충쇠감과정,발현맥충상승시간약위2 ns,차불수외가편압영향,이맥충쇠감과정가분위3계단.이용α입자결합비행시간기술연구료 CdZnTe 정체적재류자전수특성,분석료결구결함적산사화부획-구부획대재류자전수특성적영향.동시대비료불동후도적 CdZnTe탐측기재불동전압하대맥충 X 사선적향응특성.결과표명,당외가전장강도증가시,유도맥충전류곡선적반봉관정지수쇠감,단당탐측기후도대우0．2 mm 시,수착탐측기후도적증가변화불명현.가능시유우재료중결구결함적농도증가,대재류자적부획화산사작용가극,엄중영향료재류자적전수과정화복합시간.
As-grown high resistive CdZnTe crystals were employed to fabricate planar detectors.The pulsed X-rays induced transient current waveforms were obtained at room temperature.The rise time and decay time of the transient currents were evaluated.The rise time is approximately of 2 ns,which is independent on the bias voltage.The current decay can be divided into 3 parts.The charge transport behaviors were analyzed usingαparticles induced pulses combining with time of flight technique.The effects of structure defects on the charge carrier scattering and trapping-detrapping were discussed.In addition,the transient current waveforms of CdZnTe detectors with different thickness were compared as a function of bias voltage.The full wave at half maximum (FWHM)of the transient currents is exponential decay as the bias increases.However,the variation is limited when the detector is thicker than 0.2 mm,which is possibly attributed to the increasing trapping and scattering centers in the materials.Thus,the charge transport properties were degraded and the recombination time was prolonged.