REASSESSMENT OF THE ASSIGNMENT OF THE INM2-VI COMPOUNDS(3+VM2+ DEFECTIN CDTE AND TERNARY II)

Previous perturbed angular correlation (PAC) spectroscopy measurements on the donor indium in CdTe and its alloys have revealed several defe ct complexes. One defect characterized by two sets of quadrupole inter action parameters, nu(Q)=83 MHz, eta=0.08 and nu(Q)=99 MHz, eta=0.08, was observed in Hg0.8Cd0.2Te (x=0.2 MCT) and attributed to the substit utional indium-metal vacancy complex InM2+3+VM2+. A defect characteriz ed by nu(Q)=61+/-1 MHz and asymmetry parameter eta between 0 and 0.19 was seen in CdTe and widely attributed to the same complex. Both of th ese assignments were based mainly on an observed relationship between complex formation and the loss of metal ions. In this article we prese nt PAC measurements on In-111-doped x=0.45 MCT (Hg0.55Cd0.45Te). These measurements reveal defects having quadrupole interactions very simil ar to those seen previously in CdTe and in x=0.2 MCT. Two unique defec t fractions f(1) and f(2), characterized by nu(Q1)=60+/-3 MHz, (eta 1) approximate to 0-0.2, and nu(Q2)=87+/-4 MHz, (eta 2)approximate to 0-0 .15, were seen in x=0.45 MCT, in some cases simultaneously. The observ ation of both of-these interactions in the same material-if they corre spond to the defects seen in CdTe and x=0.21 MCT-precludes the possibi lity that they both correspond to precisely the same defect. We also o bserved a change in the relative fractions of these two defects with t ime at room temperature; the fraction f(2) vanished over a period of a day, while f(1) and f(0) (the fraction of indium atoms in sites havin g cubic or higher symmetry) increased. While we cannot rule out the po ssibility of a slow electronic transition, at present we favor a model in which one of the interactions (probably the one near 60 MHz) corre sponds to a complex in which indium is paired to a fast-diffusing mono valent metal ion Like Ag+, Cu+, or Li+. (C) 1995 American Institute of Physics.