Photoluminescence study of basal plane stacking faults in ZnO nanowires

We have investigated the photoluminescence (PL) of ZnO nanowires (NWs) containing a high density (~1×106 cm-1) of basal plane stacking faults (BSFs). It was observed that the BSFs result in a specific PL peak at ~3.329 eV along with a donor bound excitonic emission (DoX) peak at 5 K. The observed BSF-related emission is of excitonic type and possesses longer PL lifetime than DoX (~360 ps vs. ~70 ps). Via comparison of the microstructural and the PL properties of the ZnO NWs, it is shown that the observed BSF-related emission is due to the formation of crystal phase quantum wells (QWs). This is explained by the fact that BSF in wurtzite (WZ) ZnO is the thinnest segment of zinc blende (ZB) phase ZnO inserted in the WZ matrix, resulting in band alignment of type II due to the conduction and valence band offsets of ZB with respect to WZ ZnO. The mechanism of the BSF related PL is suggested to be an indirect exciton transitions due to the recombination of electrons confined in the ZB QWs to holes in the WZ barriers localized near the BSFs. © 2013 Elsevier B.V. All rights reserved

Міністерство фінансів України як головний орган управління державними фінансами

The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.Funding Agencies|EC FP-7 International Research Staff Exchange Scheme (IRSES) Grant [318520]; Linkoping Linnaeus Initiative for Novel Functional Materials (LiLi-NFM); European Union [604391]; Swedish Research Council (VR) Marie Sklodowska Curie International Career Grant [2015-00679]</p