Dynamical Characteristics of Isolated Donors, Acceptors and Complex Defect Centers in Novel ZnO

Novel wide bandgap ZnO, BeO and ZnBeO materials have recently gained considerable interest due to their stellar optoelectronic properties. These semiconductors are being used in developing high-resolution flexible transparent nanoelectronics/photonics and achieving high-power radio frequency modules for sensors/biosensors, photodetectors/solar cells, resistive random-access memory applications. Despite earlier evidence of attaining p-type wz ZnO with N doping, the problem persists to accomplish reproducible p-type conductivity. This issue is linked to charge compensation by intrinsic donors and/ or background impurities. In ZnO : Al (Li), the vibrational features by infrared and Raman spectroscopy have ascribed the presence of isolated AlZn(LiZn) defects; nearest neighbor (NN) [AlZn-NO] pairs; and 2nd NN [AlZn-O-LiZn;VZn-O-LiZn] complexes. However, no firm identification has been established. By integrating accurate perturbation models in a realistic Green’s function method, we have meticulously simulated impurity vibrational modes of AlZn (LiZn) and their bonding to form complexes with dopants as well as intrinsic defects. We strongly feel that these phonon features in doped ZnO will encourage spectroscopists to perform similar measurements to check our theoretical conjectures.