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Transition-edge sensor (TES) microcalorimeters are advanced cryogenic detectors that use a superconducting film for particle or photon detection. We are establishing a new production line for TES detectors to serve as cryogenic anticoincidence (i.e., veto) devices. These detectors are made with a superconducting bilayer of titanium (Ti) and gold (Au) thin films deposited via electron beam evaporation in a high vacuum condition on a monocrystalline silicon substrate. In this work, we report on the development of such sensors, aiming to achieve stable sensing performance despite the effects of aging. For this purpose, patterned and non-patterned Ti/Au bilayer samples with varying geometries and thicknesses were fabricated using microfabrication technology. To characterize the detectors, we present and discuss initial results from repeated resistance–temperature (R–T) measurements over time, conducted on different samples, thereby augmenting existing literature data. Additionally, we present a discussion of the sensor's degradation over time due to aging effects and test a potential remedy based on an easy annealing procedure. In our opinion, this work establishes the groundwork for our new TES detector production line. [ABSTRACT FROM AUTHOR]

This paper presents the analysis and development of an evanescent waveguide sensor system, based on a hydrogenated amorphous silicon (a-Si:H) photodiode and a double ion-exchanged waveguide diffused in a borosilicate BK7 glass substrate. The a-Si:H sensor is a p-doped/intrinsic/n-doped diode, with a metal top electrode and an indium tin oxide (ITO) transparent bottom contact. Simulations on the confinement of a monochromatic light in a channel waveguide and its coupling into a thin-film photodetector were performed using COMSOL Multiphysics. The system design considers a deep investigation on refractive index and thickness of the ITO layer, which are key parameters for the optical coupling optimization between the waveguide and the photodetector. The first prototype was made using standard microelectronics techniques: physical and chemical vapor deposition of the thin films of the structure, wet and dry etching of the different materials, and photolithography for the thin-film pattern definition. The electrooptical characterization of the fabricated device shows the effectiveness of the optical coupling and suggests its use for on-chip detection in lab-on-chip applications. [ABSTRACT FROM AUTHOR]