Ammonium Fluoride Passivation of CdZnTeSe Sensors for Applications in Nuclear Detection and Medical Imaging
Ammonium Fluoride Passivation of CdZnTeSe Sensors for Applications in Nuclear Detection and Medical Imaging
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DOI：
10.3390/s19153271
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发表时间：
2019-08-01
期刊：
影响因子：
3.9
通讯作者：
James, Ralph B.
中科院分区：
文献类型：
--
作者：
Egarievwe, Stephen U.;Roy, Utpal N.;James, Ralph B.
硒化镉锌（Cd1-xZnxTe1-ySey 或 CZTS）是新兴的 CdTe 基半导体材料之一，用于在室温或接近室温（即无需低温冷却）下检测 X 射线和伽马射线辐射。 CZTS 传感器的潜在应用包括医学成像、X 射线检测和伽马射线光谱。需要对CZTS进行化学钝化以降低富Te表面的电导率，从而降低噪声并提高器件性能。在本研究中，我们重点研究使用 10% 氟化铵水溶液对 CZTS 表面钝化的影响。研究了化学处理对漏电流、以电子迁移率-寿命 (mu tau) 乘积测量的电荷传输以及以特定峰的半峰全宽 (FWHM) 测量的光谱分辨率的影响。钝化后，漏电流增加并开始下降至钝化前的水平。记录了 -35 V 至 -200 V 之间八个施加电压的能量分辨率。结果显示，Am-241 的 59.6 keV 伽马峰探测器的能量分辨率平均提高了 25%。电子 mu tau 积未变化，为 2 x 10(-3) cm(2)/V。这些结果表明氟化铵对于 CZTS 探测器的化学钝化是有效的。
Cadmium zinc telluride selenide (Cd1-xZnxTe1-ySey or CZTS) is one of the emerging CdTe-based semiconductor materials for detecting X- and gamma-ray radiation at or near room temperature (i.e., without cryogenic cooling). Potential applications of CZTS sensors include medical imaging, X-ray detection, and gamma-ray spectroscopy. Chemical passivation of CZTS is needed to reduce the conductivity of Te-rich surfaces, which reduces the noise and improves the device performance. In this study, we focus on the effect of surface passivation of CZTS using a 10% aqueous solution of ammonium fluoride. The effects of the chemical treatment were studied on the leakage current, charge transport measured as the electron mobility-lifetime (mu tau) product, and the spectral resolution measured as the full-width at half-maximum (FWHM) of specific peaks. After passivation, the leakage current increased and began to decrease towards pre-passivation levels. The energy resolutions were recorded for eight applied voltages between -35 V and -200 V. The results showed an average of 25% improvement in the detector's energy resolution for the 59.6 keV gamma peak of Am-241. The electron mu tau product was unchanged at 2 x 10(-3) cm(2)/V. These results show that ammonium fluoride is effective for chemical passivation of CZTS detectors.