Dr. Egle Zemaityte Profile

Dr. Egle Zemaityte

at Leonardo UK Ltd

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Author

Publications (5)

Proceedings Article | 7 June 2024 Presentation + Paper

Visible to SWIR eAPD performance

L. Hipwood, C. Maxey, E. Zemaityte, D. Owton, S. Bains, I. Baker, A. Reed, M. Hicks, A. D'Souza

Proceedings Volume 13030, 1303004 (2024) https://doi.org/10.1117/12.3014072

KEYWORDS: Mercury cadmium telluride, Etching, Sensors, Quantum efficiency, Spectral response, Avalanche photodetectors, Readout integrated circuits, Passivation, Short wave infrared radiation, Zinc sulfide

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A NASA Advanced Component Technology (ACT) program targeted development of electron avalanche photodiodes (eAPDs) that spanned the 500 nm to 2500 nm spectral range. This ACT task leveraged an existing eAPD that are used by astronomers and other NASA programs. However, the existing eAPD cut-on wavelength starts at 800 nm, due to the CdTe buffer layer through which photons have to traverse prior to reaching the HgCdTe absorber layer. This ACT task extended the eAPD detectors cut-on wavelength down to the visible wavelength range, which required the removal of the GaAs substrate and the CdTe buffer layer. The most challenging portion of the project was the development of a passivation layer at the illuminating surface that transmits photons between 500 nm and 2500 nm, while minimizing surface recombination velocity at the surface to maintain low dark current. The baseline was to demonstrate an eAPD with 500 nm cuton wavelength, with a goal of extending the cut-on wavelength into UV. A critical task on the program was development of a passivation process to drive minority carriers away from the passivant/HgCdTe interface towards the gain region. Two potential passivants were investigated. Results of the experiments showed one variant gave the best results and has been chosen as the deposition method. Progress was made in the development of visible to SWIR APDs in that QE was measured to be flat across the 500 nm to 2500 nm band but was low ~ 15% for one of the arrays. Another APD array had QE as high as 28%. The contention is that etching for the two arrays was different resulting in different HgCdTe absorber thickness values. Low QE is probably because the thickness of the absorber may be approximately equal to or longer than the diffusion length. Consequently, the thinner absorber regions result in higher QE, whereas the thicker absorber region of the array result in lower QE. Gain as a function of bias was measured and gain M ranged from ~ 25 to 50 at 10 V bias exceeding the M = 10 at 10 V requirement. Improving QE in the future will be by etching further into the HgCdTe absorber. This will reduce the distance that the carriers have to diffuse to reach the junction and should increase the QE.

Proceedings Article | 29 August 2022 Presentation + Paper

First tests of a 1 megapixel near-infrared avalanche photodiode array for ultra-low background space astronomy

Charles-Antoine Claveau, Michael Bottom, Shane Jacobson, Klaus Hodapp, Aidan Walk, Markus Loose, Ian Baker, Egle Zemaityte, Matthew Hicks, Keith Barnes, Richard Powell, Ryan Bradley, Eric Moore

Proceedings Volume 12191, 121910Z (2022) https://doi.org/10.1117/12.2627285

KEYWORDS: Sensors, Astronomy, Mercury cadmium telluride, Avalanche photodiodes

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Proceedings Article | 29 August 2022 Poster + Paper

Design and manufacture of the carrier and flex cable for the Leonardo 1K

A. Vaccarella, N. Herrald, R. Sharp, J. Gilbert, M. Ellis, E. Zemaityte, M. Hicks

Proceedings Volume 12191, 121912D (2022) https://doi.org/10.1117/12.2629916

KEYWORDS: Sensors, Interfaces, Thermal modeling, Tolerancing, Manufacturing, Temperature metrology, Design for manufacturability, Finite element methods, Signal detection, Aluminum

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Proceedings Article | 26 August 2022 Presentation + Paper

Linear-mode avalanche photodiode arrays in HgCdTe at Leonardo UK

Egle Zemaityte, Dan Owton, Chris Maxey, Jim Gordon, Vincent Isgar, Les Hipwood, Matthew Hicks, Keith Barnes, Peter Thorne, Ian Baker

Proceedings Volume 12183, 1218317 (2022) https://doi.org/10.1117/12.2634331

KEYWORDS: Mercury cadmium telluride, Astronomy, Avalanche photodetectors, Telescopes, Readout integrated circuits, Sensors, Wavefront sensors, Doping

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Proceedings Article | 30 May 2022 Presentation + Paper

Infrared APD detectors for high bandwidth applications

A. D'Souza, V. Khalap, I. Baker, E. Zemaityte, I. Prighozin, E. Bellotti

Proceedings Volume 12091, 1209104 (2022) https://doi.org/10.1117/12.2619237

KEYWORDS: Sensors, Avalanche photodetectors, Semiconducting wafers, Monte Carlo methods, Signal detection, Mercury cadmium telluride, Readout integrated circuits, Particles, Diffusion, Manufacturing

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