Ion-milling-assisted study of defect structure of acceptor-doped HgCdTe heterostructures grown by molecular beam epitaxy

摘要

The effect of ion milling on electrical properties of vacancy- and arsenic-doped p-Hg_(1-x)Cd_xTe (MCT) (x ～ 0.22) has been studied. Samples for the study were fabricated by thermal annealing of n-type heterostructures grown by molecular beam epitaxy (MBE) on GaAs. Their behaviour under ion milling was compared to that of MCT bulk samples and films grown by liquid and vapour phase epitaxy. Residual donor concentration in the MBE-grown structures was found to be of the order of 10~(15) cm~(-3), which is typical for MCT. Unique to the MBE structures was high electron concentration (～10~(17) cm~(-3)) straight after the milling. We suppose that this fact reflected ion-milling-induced activation of an initially neutral defect, which was formed in the heterostructures during the growth. A possible nature of the defect is discussed.