Tc Modulation on Iridium-Based Transition Edge Sensor

Abstract

Iridium is one of the most chemically stable materials and, therefore, suitable for high-performance transition edge sensor (TES) detectors for space applications, where long-term stability (spanning around five to ten years) is required. Thanks to their high stability, these TES detectors could be employed for high-end technological applications, such as nuclear/particle physics, single photon, and X-ray detection. Studying T_c modulation induced via surface modifications and patterning is an important aspect for the fine-tuning of these detectors. Focused ion beam (FIB) is a suitable method to pattern the material surfaces up to the nanometric scale, which can be applied for material characterization. Thus, this method has been applied in our work to characterize the superconductive transition behavior of 100-nm-thick Ir films (grown on a Si substrate). Here, we report a mechanism to modulate T_c after FIB patterning. Periodic holes forming either hexagonal or square arrays, with various hole-to-hole distances, were realized and characterized at low temperature. A preliminary simulation has been reported studying the possible behavior of T_c after FIB patterning.