The crystal geometry and the aspect ratio effects on spectral performance of CdZnTe Frisch collar device

Abstract

The effects of crystal geometry and aspect ratio on a CdZnTe Frisch collar device were investigated. A 19.08x19.34x4.95mm 3 device fabricated from CdZnTe grown by Redlen Technologies was used as the starting material. The crystal was re-fabricated many times to achieve several aspect ratios while the device length was held constant at 4.75±0.15mm. The following aspect ratios were successfully fabricated from the initial device: 0.26, 0.52, 0.71, 0.96, 1.19, 1.36, 1.59 and 1.92. The energy spectra of 241 Am and 137 Cs were recorded for all devices in both planar and Frisch collar configurations. The current-voltage (I-V) characteristic curve was also determined for planar configurations. It was observed that the Frisch collar effect begins to occur for devices with an aspect ratio of approximately 1.0. Device performance continued to improve as the aspect ratio was further increased and was noted to significantly improve the energy resolution of the device when the aspect ratio was greater than 1.5. The CdZnTe devices were also theoretically modeled to support the experimental conclusion.