Date: November 18, 2020
Oleksandr Grynko with co-authors: Tristen Thibault, Emma Pineau, Gytis Juska and Alla
Reznik, published the paper “Bilayer lead oxide X-ray photoconductor for lag-free operation” in
the Scientific Reports – Nature. Congratulations Oleksandr on this published paper.
Polycrystalline Lead Oxide (poly-PbO) was considered one of the most promising
photoconductors for the direct conversion X-ray medical imaging detectors due to its previous
success in optical imaging, i.e., as an optical target in so-called Plumbicon video pick-up tubes.
However, a signal lag which accompanies X-ray excitation, makes poly-PbO inapplicable as an
X-ray-to-charge transducer in real-time X-ray imaging. In contrast, the recently synthesized
Amorphous Lead Oxide (a-PbO) photoconductor is essentially lag-free. Here, we report on our
approach to a PbO detector where a thin layer of a-PbO is combined with a thick layer of poly-
PbO for lag-free operation. In the presented a-PbO/poly-PbO bilayer structure, the poly-PbO
layer serves as an X-ray-to-charge transducer while the a-PbO acts as a lag prevention layer. The
hole mobility in the a-PbO/poly-PbO bilayer structure was measured by photo-Charge Extraction
by Linearly Increasing Voltage technique at different temperatures and electric fields to
investigate charge transport properties. It was found that the hole mobility is similar to that in a-
Se—currently the only commercially viable photoconductor for the direct conversion X-ray
detectors. Evaluation of the X-ray temporal performance demonstrated complete suppression of
signal lag, allowing operation of the a-PbO/poly-PbO detector in real-time imaging.
Continue reading the article: https://doi.org/10.1038/s41598-020-77050-w