Columnar recombination for X-ray generated electron-holes in amorphous selenium and its significance in a-Se x-ray detectors

Journal Article · Mon Mar 28 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4944880· OSTI ID:22594520

Bubon, O. ^[1]; Jandieri, K.; Baranovskii, S. D. ^[2]; Kasap, S. O. ^[3]; Reznik, A. ^[4]

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1. Chemistry and Material Science PhD Program, Lakehead University, Thunder Bay, Ontario, P7B 5E1 (Canada)
2. Department of Physics and Material Sciences Centre, Philipps University Marburg, D-35032 Marburg (Germany)
3. Department of Electrical Engineering, University of Saskatchewan, Saskatoon, SK, S7N 5A2 (Canada)
4. Thunder Bay Regional Research Institute, Thunder Bay, Ontario, P7A 7T1 (Canada)

Although amorphous selenium (a-Se) has a long and successful history of application in optical and X-ray imaging, some of its fundamental properties are still puzzling. In particularly, the mechanism of carrier recombination following x-ray excitation and electric field and temperature dependences of the electron-hole pair creation energy (W{sub ehp}) remain unclear. Using the combination of X-ray photocurrent and pulse height spectroscopy measurements, we measure W{sub ehp} in a wide range of temperatures (218–320 K) and electric fields (10–100 V/µm) and show that the conventional columnar recombination model which assumes Langevin recombination within a column (a primary electron track) fails to explain experimental results in a wide range of electric fields and temperatures. The reason for the failure of the conventional model is revealed in this work, and the theory of the columnar recombination is modified to include the saturation of the recombination rate at high electric field in order to account for the experimental results in the entire range of fields and temperatures.

• OSTI ID: 22594520
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 12; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
AMORPHOUS STATE
CARRIERS
ELECTRIC FIELDS
ELECTRONS
EXCITATION
FAILURES
HEIGHT
HOLES
IMAGES
PAIR PRODUCTION
PARTICLE TRACKS
PHOTOCURRENTS
PULSES
RECOMBINATION
SATURATION
SELENIUM
SPECTROSCOPY
TEMPERATURE DEPENDENCE
X RADIATION