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Performance evaluation of a new 30 µm thick GaAs x-ray detector grown by MBE

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posted on 2023-06-09, 23:11 authored by Grammatiki LioliouGrammatiki Lioliou, C L Poyser, J Whale, R P Campion, A J Kent, Anna BarnettAnna Barnett
A circular mesa (400 µm diameter) GaAs p+-i-n+ photodiode with a 30 µm thick i layer was characterized for its performance as a detector in photon counting x-ray spectroscopy at 20 °C. The detector was fabricated from material grown by molecular beam epitaxy (MBE). An earlier MBE-grown detector fabricated using a different fabrication process and material from a different area of the same epiwafer was shown to suffer from: relatively high leakage current at high temperatures; a high effective carrier concentration that limited its depletion layer width; and material imperfections (butterfly defects) [Lioliou et al 2019 Nucl. Instrum. Methods Phys. Res. A 946 162670]. However, the new detector has better performance (lower leakage current and effective carrier concentration within the i layer). Using the new detector and low noise readout electronics, an energy resolution of 750 eV ± 20 eV Full Width at Half Maximum (FWHM) at 5.9 keV was achieved at 20 °C, equal to that reported for high quality GaAs detectors made from high quality material grown by metalorganic vapour phase epitaxy [Lioliou et al 2017 J. Appl. Phys. 122 244506]. The results highlight the substantially different performances of detectors made from the same epiwafer when the wafer qualities are not uniform and the effects of different fabrication processes.

History

Publication status

  • Published

File Version

  • Published version

Journal

Materials Research Express

ISSN

2053-1591

Publisher

IOP Publishing

Issue

2

Volume

8

Page range

1-6

Article number

a025909

Department affiliated with

  • Physics and Astronomy Publications

Research groups affiliated with

  • Space Research Group Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2021-03-03

First Open Access (FOA) Date

2021-03-03

First Compliant Deposit (FCD) Date

2021-03-01

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