Institute for Microelectronics and Microsystems, IMM-CNR, Via Monteroni, 73100 Lecce, Italy.
Institute of Nanotechnology, NANOTEC-CNR, Via Monteroni, 73100 Lecce, Italy.
Sensors (Basel). 2023 May 16;23(10):4795. doi: 10.3390/s23104795.
In radiation detectors, the spatial distribution of the electric field plays a fundamental role in their operation. Access to this field distribution is of strategic importance, especially when investigating the perturbing effects induced by incident radiation. For example, one dangerous effect that prevents their proper operation is the accumulation of internal space charge. Here, we probe the two-dimensional electric field in a Schottky CdTe detector using the Pockels effect and report on its local perturbation after exposure to an optical beam at the anode electrode. Our electro-optical imaging setup, together with a custom processing routine, allows the extraction of the electric-field vector maps and their dynamics during a voltage bias-optical exposure sequence. The results are in agreement with numerical simulations, allowing us to confirm a two-level model based on a dominant deep level. Such a simple model is indeed able to fully account for both the temporal and spatial dynamics of the perturbed electric field. This approach thus allows a deeper understanding of the main mechanisms affecting the non-equilibrium electric-field distribution in CdTe Schottky detectors, such as those leading to polarization. In the future, it could also be used to predict and improve the performance of planar or electrode-segmented detectors.
在辐射探测器中，电场的空间分布在其工作中起着至关重要的作用。获取这种场分布具有战略意义，特别是在研究入射辐射引起的干扰效应时。例如，一种阻止其正常运行的危险效应是内部空间电荷的积累。在这里，我们使用泡克尔斯效应探测肖特基 CdTe 探测器中的二维电场，并报告在阳极电极处暴露于光束后其局部扰动。我们的电光成像装置与自定义处理例程相结合，允许提取电场矢量图及其在电压偏置-光学曝光序列过程中的动态。结果与数值模拟一致，使我们能够确认基于主导深能级的两级模型。这种简单的模型确实能够完全解释受扰电场的时间和空间动态。这种方法因此可以更深入地了解影响 CdTe 肖特基探测器中非平衡电场分布的主要机制，例如导致极化的机制。将来，它还可以用于预测和改善平面或分段电极探测器的性能。
