Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

M. Kopytko, J. Wróbel, K. Jóźwikowski, A. Rogalski, Jarek Antoszewski, Nima Akhavan, Gilberto A. Umana-Membreno, Lorenzo Faraone, C.R. Becker

    Research output: Contribution to journalArticlepeer-review

    42 Citations (Scopus)


    Design of practically realizable unipolar HgCdTe nBn photodetectors has been studied in detail by numerical analysis. The simulations reported herein reveal that, by optimization of barrier doping, dark current levels can be reduced and collection efficiency substantially improved. It is shown that p-type doping of the barrier layer can significantly reduce the effective potential barrier arising from the valence band offset between the absorber and barrier regions, thus enabling HgCdTe nBn detector operation under near zero-bias conditions. However, relatively high electric fields in the space charge regions near the barrier/absorber interface result in enhanced trap-assisted Shockley–Read–Hall thermal generation. Our calculations indicate that nBn HgCdTe detectors with barriers engineered by use of HgTe/Hg0.05Cd0.95Te superlattices have, potentially, substantially better valence band alignment without the need for p-type doping.
    Original languageEnglish
    Pages (from-to)158-166
    Number of pages9
    JournalJournal of Electronic Materials
    Issue number1
    Publication statusPublished - Jan 2015


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