Tellurium doped a-Se devices for improved optical absorption in indirect x-ray photodetection

Kaitlin Hellier; Emmie Benard; Shiva Abbaszadeh

doi:10.1117/12.2613150

4 April 2022 Tellurium doped a-Se devices for improved optical absorption in indirect x-ray photodetection

Kaitlin Hellier, Emmie Benard, Shiva Abbaszadeh

Proceedings Volume 12031, Medical Imaging 2022: Physics of Medical Imaging; 120310H (2022) https://doi.org/10.1117/12.2613150
Event: SPIE Medical Imaging, 2022, San Diego, California, United States

Abstract

Amorphous selenium (a-Se) is a high gain, low dark current, large area compatible photoconductor that has received significant attention towards the development of UV and X-ray detectors for medical imaging. Indirect detectors utilizing a-Se often feature blue emitting scintillators due to the high attenuation coefficient of a-Se in that region. However, emission tails from the scintillators often fall out of the conversion range of a-Se, and scintillators with emission peaks outside the absorption of Se cannot be utilized. In order to improve the sensitivity and gain in a-Se indirect detectors, we propose doping a-Se with tellurium as a function of depth, where tail emission will be absorbed by the lower bandgap aSe/Te after primary absorption in the initial Se layer. In addition, we employ a lateral device structure to avoid any absorption at short wavelengths from a transparent electrode or blocking layer. In this work, we present the first steps towards fabricating these devices. Studies of charge transport in doped a-Se/Te devices are performed using the transient photocurrent time-of-flight technique. We report hole and electron mobilities for a-Se_1-xTe_x(x = 0, 0.01, 0.05, 0.10) as a function of applied voltage, along with band gaps and comparisons to previous studies. Fabrication of lateral devices, with and without optical slits, is demonstrated and discussed.

Conference Presentation

Citation Download Citation

Kaitlin Hellier, Emmie Benard, and Shiva Abbaszadeh "Tellurium doped a-Se devices for improved optical absorption in indirect x-ray photodetection", Proc. SPIE 12031, Medical Imaging 2022: Physics of Medical Imaging, 120310H (4 April 2022); https://doi.org/10.1117/12.2613150

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