AlInP X-ray photodiodes without incomplete charge collection noise

Zhao, S, Lioliou, G, Butera, S, Krysa, A B and Barnett, A M (2020) AlInP X-ray photodiodes without incomplete charge collection noise. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 960. a163606. ISSN 0168-9002

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Previously, an Al0.52In0.48P p+-i-n+ spectroscopic photon counting X-ray photodiode with 2 μm thick i layer (200 μm diameter) was shown to suffer from energy-dependent incomplete charge collection noise [Lioliou et al., 2019, Nucl. Instr. and Meth. A Vol. 943, Art. No. 162467]. Subsequent measurements on a larger (400 μm diameter) Al0.52In0.48P p+ -i-n+ photodiode (reported here) revealed
the presence of even greater incomplete charge collection noise. Given these findings, an expectation would have been that thicker Al0.52In0.48P structures (which would be required for efficient absorption of all but the softest X-rays) would have a greater incomplete charge collection noise contribution, thus suggesting that thick Al0.52In0.48P photodiodes may be of limited practicality as high performance detectors for photon counting X-ray spectroscopy. However, two new Al0.52In0.48P p+ -i-n+ photodiodes (with 6 μm i layers) were fabricated from material grown by the same technique (metalorganic vapour phase epitaxy) in the same reactor, and are now shown here to exhibit no signs of detectable incomplete charge collection noise under the illumination of X-ray photons of energy 4.95 keV to 21.17 keV. As such, now that greater experience has been built with Al0.52In0.48P, concerns about incomplete charge collection noise in X-ray detectors made from the material appear to have been unwarranted; the path towards thick Al0.52In0.48P X-ray detectors is now clear.

Item Type: Article
Additional Information: This work was supported by the Engineering and Physical Sciences Research Council, UK, via grant EP/P021271/1 (University of Sussex, A.M.B., PI) and in part by the Science and Technology Facilities Council, UK, via grants ST/P001815/1 and ST/R001804/1 (University of Sussex, A.M.B.,PI). A.M.B acknowledges funding received from The Leverhulme Trust, UK, in the form of a 2016 Philip Leverhulme Prize. The authors are grateful to R.J. Airey and S. Kumar at the EPSRC National Epitaxy Facility for device fabrication.
Keywords: X-ray fluorescence spectroscopy; photodiode; Aluminium Indium Phosphide; incomplete charge collection noise; energy response
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Research Centres and Groups: Space Research Group
Depositing User: Lucy Arnold
Date Deposited: 03 Mar 2020 08:29
Last Modified: 03 Mar 2020 08:30

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Project NameSussex Project NumberFunderFunder Ref
Photon counting X-ray and gamma-ray spectroscopy with Al0.52In0.48P detectorsG2140EPSRC-ENGINEERING & PHYSICAL SCIENCES RESEARCH COUNCILEP/P021271/1
Novel X-ray/[gamma]-ray DetectorsG2260STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/R001804/1