Large area thin-film photoconductor offers superior performance over amorphous selenium (a-Se) for direct detection systems


Project ID: D2014-09

Invention Description and Novelty: Radiation detector device utilizes polycrystalline cadmium telluride (CdTe) thin films (less than 1 mm thick) with superior radiation hardness and better detection efficiency for both high energy (megaelectron volt--MeV) and low energy (kiloelectron volt--keV) range X-rays. Physical properties of CdTe include mechanical and chemical stability, high atomic number of 50, low ionization energy, large band gap and outstanding radiation hardness which make it a very attractive choice for these detection systems.

Using easier to grow and typically thinner polycrystalline semiconductor films, this novel technology utilizes a photovoltaic (PV) mode of operation which provides the built-in electric field. Unique technology establishes a range of optimal parameters producing the highest detective quantum efficiency (DQE) due to energy absorption, as well as signal and noise spatial spreading. The results of absorbed energy simulation were used in device operation modeling to predict the detector output signal, and modeling results have been verified experimentally to establish the lowest considered device thickness. Data is available showing that this detector based on CdTe is capable of achieving a higher resolution as well as higher quantum efficiency than previously available systems.

Value Proposition: Use of polycrystalline photoconductors such as CdTe in direct detection systems offers the following benefits:

·        Simpler device structure resulting in lower manufacturing cost

·        High potential of providing images of superior contrast and sharpness due to inherently low signal spreading within the detector.

·        Materials with high atomic numbers are of particular interest for these systems due to their enhanced x-ray absorption, leading to higher signal to noise ratio.

·        High mobility-lifetime product provides effective charge collection 

Applications: Diagnostic X-ray imaging, electronic portal imaging device (EPID), CT scanner detectors or devices including cone beam CT imaging 

IP Status: Provisional Application Filed

Patent Information:
For Information, Contact:
Anne Izzi
Licensing Associate
The University of Toledo
419 530 6226
E. Parsai
Diana Shvydka