The unambiguous type conversion of GaAs by electron irradiation is reported here for the first time. Several highhyphen;qualitynhyphen;type vaporhyphen;phase epitaxial layers (rgr;quest;3 OHgr;thinsp;cm and mgr;quest;7000 cm2/Vthinsp;sec at 300 K) were converted by 1hyphen;MeV electrons to highhyphen;qualityphyphen;type layers (rgr;quest;30 OHgr;thinsp;cm and mgr;quest;400 cm2/Vthinsp;sec). Temperaturehyphen;dependent Hallhyphen;effect data show energy levels at 0.5, 0.3, and about 0.1 eV above the valence band. Evidence is presented to indicate that the failure of some of our samples (and, perhaps, other samples reported in the literature) to convert tolowhyphen;resistivityptype is due to a rather high concentration of ashyphen;grown deep levels which pin the Fermi level near midgap.
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