Browsing by Author "Dell, JM"

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    Characterisation of arsenic doped HgCdTe grown by molecular beam epitaxy
    (IEEE, 2006-12-06) Tsen, GK; Sewell, RH; Atanacio, AJ; Prince, KE; Musca, CA; Dell, JM; Antoszewski, J; Faraone, L
    Extrinsic p-type doping of Mercury Cadmium Tel-luride (HgCdTe) epilayers grown by Molecular Beam Epitaxy (MBE) was carried out with an arsenic (As) cracker cell. As-grown samples were characterised via Fourier Transform Infrared Transmission Spectrometry (FTIR), Secondary Ion Mass Spectrometry (SIMS) as well as variable field magneto-transport measurements coupled with the quantitative mobility spectrum analysis (QMSA) to study the Hall effect characteristics. Arsenic activation annealing of the samples were performed and magneto-transport measurements repeated. Results indicate that as-grown samples show n-type behaviour indicating that arsenic incorporate as donors in the material with annealed samples showing p-type characteristics with heavy compensation. © Copyright 2006 IEEE
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    Incorporation and activation of arsenic in MBE-grown HgCdTe
    (IOP Publishing, 2007-12-12) Tsen, GK; Sewell, RH; Atanacio, AJ; Prince, KE; Musca, CA; Dell, JM; Faraone, L
    Research into p-type doping of HgCdTe with arsenic has concentrated on the use of a conventional effusion cell and optimization of growth conditions to achieve an increase in incorporation efficiency. This study investigates the use of a cracker cell, which is now the preferred method of doping HgCdTe due to its higher arsenic incorporation efficiency under optimum growth conditions. A detailed investigation of a number of arsenic doped HgCdTe layers grown on CdZnTe substrates by molecular beam epitaxy using a cracker cell as a source of arsenic is presented. Growth parameters influencing the amount of arsenic incorporated, such as the cracker-cell bulk temperature and substrate temperature, were investigated. Arsenic depth profiles were obtained via detailed secondary ion mass spectrometry where all major constituents in the epilayers were analysed. Magneto-transport Hall measurements were performed on as-grown material and those that underwent high-temperature anneals typical for arsenic activation. Using the quantitative mobility spectrum analysis technique, contributions to total conductivity arising from various carriers present in the samples have been separated. As-grown samples were found to exhibit n-type behaviour consistent with arsenic incorporating on cation sublattice, while samples that underwent high-temperature annealing show partial activation of arsenic with electron compensation. © Copyright 2007 IOP Publishing