Characterization of a 15 $\mu m$ Cutoff HgCdTe Detector Array for Astronomy

TL;DR

This paper reports on the development and characterization of 13 and 15 micron cutoff HgCdTe detector arrays for space astronomy, highlighting dark current performance improvements at larger cutoff wavelengths.

Contribution

It introduces the development of 13 and 15 micron cutoff HgCdTe arrays and analyzes their dark current mechanisms, advancing detector technology for future space missions.

Findings

13 micron arrays show dark current mechanisms similar to 10 micron arrays.

15 micron array exhibits dark current two orders of magnitude lower at high bias.

Characterization informs design improvements for future detectors.

Abstract

The University of Rochester infrared detector group is working together with Teledyne Imaging Sensors to develop HgCdTe 15 $\mu m$ cutoff wavelength detector arrays for future space missions. To reach the 15 $\mu m$ cutoff goal, we took an intermediate step by developing four $\sim$13 $\mu m$ cutoff wavelength arrays to identify any unforeseen effects related to increasing the cutoff wavelength from the extensively characterized 10 $\mu m$ cutoff wavelength detector arrays developed for the NEOCam mission. The characterization of the $\sim$13 $\mu m$ cutoff wavelength HgCdTe arrays at the University of Rochester allowed us to determine the key dark current mechanisms that limit the performance of these HgCdTe detector arrays at different temperatures and bias when the cutoff wavelength is increased. We present initial dark current and well depth measurements of a 15 $\mu m$ cutoff array which shows dark current values two orders of magnitude smaller at large reverse bias than would be expected from our previous best structures.