Effect of a thin AlO_x layer on transition-edge sensor properties

TL;DR

This study investigates how adding a thin AlOx insulating layer affects the noise and thermal properties of transition-edge sensors, revealing increased noise and unexpected thermal conduction.

Contribution

It provides new insights into the impact of an insulating AlOx layer on TES device noise and thermal behavior, informing future detector design.

Findings

AlOx layer increases device noise

AlOx acts as a good thermal conductor

Insulating layer introduces internal thermal features

Abstract

We have studied the physics of transition-edge sensor (TES) devices with an insulating AlOx layer on top of the device to allow implementation of more complex detector geometries. By comparing devices with and without the insulating film, we have observed significant additional noise apparently caused by the insulator layer. In addition, AlOx was found to be a relatively good thermal conductor. This adds an unforeseen internal thermal feature to the system.