Enhanced detection efficiency of direct conversion x-ray detector using polyimide as hole-blocking layer

Shiva Abbaszadeh, Christopher C. Scott, Oleksandr Bubon, Alla Reznik, Karim S. Karim

Research output: Contribution to journalArticlepeer-review

Abstract

In this article we demonstrate the performance of a direct conversion amorphous selenium (a-Se) X-ray detector using biphenyldisnhydride/1,4 phenylenediamine (BPDA/PPD) polyimide (PI) as a hole-blocking layer. The use of a PI layer with a-Se allows detector operation at high electric fields (≥10â€...V/μm) while maintaining low dark current, without deterioration of transient performance. The hole mobility of the PI/a-Se device is measured by the time-of-flight method at different electric fields to investigate the effect of the PI layer on detector performance. It was found that hole mobility as high as 0.75â€...cm 2 /Vs is achievable by increasing the electric field in the PI/a-Se device structure. Avalanche multiplication is also shown to be achievable when using PI as a blocking layer. Increasing the electric field within a-Se reduces the X-ray ionization energy, increases hole mobility, and improves the dynamic range and sensitivity of the detector.

Original languageEnglish (US)
Article number3360
JournalScientific reports
Volume3
DOIs
StatePublished - Nov 28 2013

ASJC Scopus subject areas

  • General

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