Abstract

This thesis investigates the performance of Raytheon’s mercury-cadmium-telluride-on-silicon (MCT-on-Si) infrared detector arrays, with particular emphasis on the impact of the heteroepitaxial silicon growth process on dark current and persistence characteristics. Infrared detectors have been the cornerstone of astronomical discovery for the past four decades and remain essential for current and future flagship observatories, including the James Webb Space Telescope and the Nancy Grace Roman Space Telescope. Traditionally, the highest-performance HgCdTe (MCT) arrays are grown on lattice-matched cadmium-zinc-telluride (CZT) substrates, which are costly and limited in size. To enable low-cost, large-format arrays, Raytheon developed a process for growth of MCT on silicon wafers. The large lattice mismatch between the materials in this approach introduces defects that degrade detector performance, and these effects are systematically characterized in the present work. Analysis of the best-performing pixels in the SATIN engineering-grade array (detector V23) reveals dark current levels substantially closer to those of state-of-the-art MCT-on-CZT devices than previously reported for MCT-on-Si technology. Persistence measurements demonstrate that charge-trapping timescales span many orders of magnitude and that trapping occurs almost exclusively within the bulk active region rather than at surface states. A clear correlation is established between p-n junction implant area and performance in the metrics of dark current and linearity, driven by increased defect density in the active volume. Finally, on-sky observations obtained with the SATIN detectors are presented. The results presented here show that MCT-on-Si technology offers a viable path toward low-cost, large-format, high-performance infrared imaging arrays for future astronomical instruments.

Publication Date

5-2026

Document Type

Dissertation

Student Type

Graduate

Degree Name

Astrophysical Sciences and Technology (Ph.D.)

Department, Program, or Center

Physics and Astronomy, School of

College

College of Science

Advisor

Stefan Preble

Advisor/Committee Member

Michael Zemcov

Advisor/Committee Member

Roger Smith

Campus

RIT – Main Campus

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