Band Gap Of MgxZn1 Research Articles

Single-phase quaternary MgxZn1−xO1−ySy alloy thin films grown by pulsed laser deposition

Quaternary-alloy MgxZn1−xO1−ySy thin films were grown quasi-epitaxially on c-plane sapphire substrates by pulsed laser deposition. Single-phase wurtzite MgxZn1−xO1−ySy films with compositions of 0.07 < x < 0.21 and y ≥ 0.8 were achieved using various ceramic targets. The S contents in the quaternary alloy films were far beyond the reported solid solubility limits of S in single-phase ternary alloy ZnO1−ySy films. The bandgap of MgxZn1−xO1−ySy, inferred from optical transmission measurements, was narrower than the bandgap of MgxZn1−xO while broadened compared with that of ZnO1−ySy. The broadening effect was enhanced with the increase of Mg content. The simultaneous substitution of cation (Zn2+) and anion (O2−) by isoelectronic elements (Mg2+ and S2−) offers further flexibility for the band-gap engineering and potentially facilitates the p-type doping of ZnO.

Wet cation exchange route to semiconductor alloys: the case study of Mg<SUB align="right">xZn<SUB align="right">1-xO

We developed a novel cation exchange method to prepare the alloyed semiconductors. A series of self–assembled magnesium doped zinc oxide (MgxZn1–xO) particles were synthesised by varying the molar ratios of Mg precursor Mg5(CO3)4(OH)2•4H2O to Zn precursor ZnAc2•4H2O from 1:1 to 3:1 at different cation exchange time. Powder X–ray Diffraction (XRD) indicates that the samples are a mixture of hexagonal and cubic phases. The UV–visible (UV–vis) absorption spectra show that the band gap of MgxZn1–xO particles can be readily tuned by optimising the cation exchange time and the molar ratio of precursors. The morphology of MgxZn1–xO particles was observed by Scanning Electron Microscopy (SEM).

Effect of Mg content on structure and properties of Mg x Zn1−x O:Al UV transparent conducting films

Mg x Zn1−x O:Al (0 ≤ x ≤ 0.6) UV transparent conducting films were deposited on quartz glass by radio frequency magnetron sputtering. Effect of Mg content on structure, optical and electrical properties of Mg x Zn1−x O:Al films was investigated. There is a single phase of basic wurtzite structure of ZnO in Mg x Zn1−x O:Al films at x ≤ 0.4, and of a basic structure of cubic structure of MgO at x ≥ 0.6. The band gap can be varied from 3.27 to 5.90 eV by controlling Mg contents. The resistivity of Mg x Zn1−x O:Al films increase with increasing Mg content x due to the decrease of Al-doping efficiency. The electrical conduction of Mg x Zn1−x O:Al films can be markedly improved by increasing the Al-doping level appropriately and annealing in argon atmosphere at over 500 °C. The maximum band gap of Mg x Zn1−x O:Al films with wurtzite structure was found to be 5.35 eV when Mg content x is 0.4, and the minimum resistivity of 5.4 × 10−4 Ω cm was obtained when the Al/(Zn + Mg + Al) is 0.03 and the annealing temperature is over 500 °C. The average transmittance of Mg x Zn1−x O:Al films was higher than 86% in the wavelength region from 300 (x ≥ 0.4) to 800 nm.

Effects of In and Mg doping on properties of ZnO nanoparticles by flame spray synthesis

The Mg- and In-doped zinc oxide (MgxZn1−xO, InyZn1−yO) nanoparticles were successfully prepared by flame spray synthesis method. According to the results obtained from X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV–Vis absorption spectra, it was concluded that the Mg or In doping induced the lattice constants to change to some extent; the band gap of MgxZn1−xO also increased with respect to the decreasing band gap of InyZn1−yO. Moreover, the strong UV emission and weak visible emission were investigated by photoluminescence spectra, while the mechanisms of Mg or In doping on PL spectra have been discussed in detail.

Effect of post annealing on the band gap of MgxZn1−xO thin films

In this work, MgxZn1−xO (MZO) thin films were grown on quartz by rf magnetron sputtering technology. It was found that MZO films possess preferred c-axis orientation and exhibit hexagonal wurtzite structure up to a Mg composition of 44.26 mol%. Furthermore, the band gap determined by absorption spectra was smaller than the theoretical calculation for the as-grown MZO thin film. The band gap blueshifted initially and then redshifted with increasing the annealing temperature of the MZO films. The reason for the shift was attributed to the displacement, effusion of Mg atoms in the films and phase separation at different annealing temperatures.