Charge traps in Zn- and Mo-based oxide microstructures. The role of Mo

Abstract

Peculiarities of the point defects creation under the X-ray irradiation and the influence of Mo doping in ZnO: Mo (10 and 30%) and MoO3 micro-powders fabricated by the hydrothermal growth method were studied in detail. It has been found that some new phases other than ZnO are created upon the heavy molybdenum doping. They were tentatively ascribed to complex zinc molybdates existing in the form of platelet flakes. The MoO3 sample contained both hydrated and anhydrous MoO3 phases in the form of microneedles. The molybdenum charge state was Mo6+ before X-ray irradiation in all the materials. X-ray irradiation resulted in creation of molybdenum- and oxygen-based charge trapping centres, i.e., Mo5+ and O− or O 2 − . Part of them is expected to exist in the pure ZnO and MoO3 phases whereas the rest appears in the complex zinc molybdates.

X-ray assisted point defects creation in micron-size Zn, Mo oxide particles at liquid nitrogen temperature

“…The ZnO phase was detected only in a negligible amount the sensitivity of XRD (see [30]). The MoO3 sample was found to be the composition of anhydrous and hydrated MoO3 [29].…”

“…They were exposed to the X-ray irradiation. According to [29] the ZnO:Mo(10 %) is the multiphase compound, composed of the Wurtzite ZnO and complex zinc-and molybdenum-based oxides. The latter material phases are even more pronounced in ZnO:Mo(30 %).…”

“…The agreement between the spectra are, in general, good. Some small disagreement originates from the complexity of the EPR spectrum containing besides these resonances also the other resonance line, e.g., belonging to Mn 2+ as reported in [29,30]. The spin-Hamiltonian parameters were thus determined as follows: 𝑔 = 2.0023 ± 0.0005, 𝐵 2 0 = 19 ± 1 MHz, 𝐵 4 0 = −0.80 ± 0.05 MHz, 𝐵 4 4 = 0.80 ± 0.05 MHz.…”