Assessment of intrinsic and doped defects in Bridgman grown Cd1-xZnxTe alloys

A comprehensive experimental and theoretical study is presented to empathize the dynamical properties of Bridgman grown Cd1-xZnxTe samples. Low temperature Raman scattering study has offered an excellent testimony to the lattice phonons of the perfect alloys with a strong evidence of Te anti-site defect (TeCd) modes. An average transfer matrix (ATM) Green\u27s function (GF) method is employed to examine the isotopic shifts of localized vibrational modes (LVMs) of isolated oxygen OTe defects in CdTe and the low frequency A1 and E phonon modes of TeCd. For the nearest-neighbor (NN) OTe – VCd pair, while the ATM-GF\u27s study revealed quite different values of LVMs from the existing infrared (IR) absorption data – the results, however, provided good justification to a simple perturbation relationship of 16OTe isotopic mode. An excellent agreement between theory and IR data of impurity modes has validated the formation of NN donor–acceptor pairs and next-nearest-neighbor complex centers involving intrinsic defects. The study is important not only for empathizing the growth process of technologically important Cd1-xZnxTe alloys but also identifying the role of carrier compensation mechanism by various donors and acceptors