Display options
Cite
Park DS, Vasheghani Farahani SK, Walker M, et al. Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface. ACS Appl Mater Interfaces. 2014;6(21):18758-68doi: 10.1021/am5043388.
Park, D. S., Vasheghani Farahani, S. K., Walker, M., Mudd, J. J., Wang, H., Krupski, A., Thorsteinsson, E. B., Seghier, D., Choi, C. J., Youn, C. J., & McConville, C. F. (2014). Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface. ACS applied materials & interfaces, 6(21), 18758-68. https://doi.org/10.1021/am5043388
Park, Dae-Sung, et al. "Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface." ACS applied materials & interfaces vol. 6,21 (2014): 18758-68. doi: https://doi.org/10.1021/am5043388
Park DS, Vasheghani Farahani SK, Walker M, Mudd JJ, Wang H, Krupski A, Thorsteinsson EB, Seghier D, Choi CJ, Youn CJ, McConville CF. Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface. ACS Appl Mater Interfaces. 2014 Nov 12;6(21):18758-68. doi: 10.1021/am5043388. Epub 2014 Oct 21. PMID: 25289707.
Copy Download .nbib Format: NLM
Share it on

ACS Appl Mater Interfaces. 2014 Nov 12;6(21):18758-68. doi: 10.1021/am5043388. Epub 2014 Oct 21.

Recrystallization of highly-mismatched Be(x)Zn(1-x)O alloys: formation of a degenerate interface.

ACS applied materials & interfaces

Dae-Sung Park, Sepehr K Vasheghani Farahani, Marc Walker, James J Mudd, Haiyuan Wang, Aleksander Krupski, Einar B Thorsteinsson, Djelloul Seghier, Chel-Jong Choi, Chang-Ju Youn, Chris F McConville

Affiliations

  1. Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom.

PMID: 25289707 DOI: 10.1021/am5043388

Abstract

We investigate the effect of thermally induced phase transformations on a metastable oxide alloy film, a multiphase Be(x)Zn(1-x)O (BZO), grown on Al2O3(0001) substrate for annealing temperatures in the range of 600-950 °C. A pronounced structural transition is shown together with strain relaxation and atomic redistribution in the annealed films. Increasing annealing temperature initiates out-diffusion and segregation of Be and subsequent nucleation of nanoparticles at the surface, corresponding to a monotonic decrease in the lattice phonon energies and band gap energy of the films. Infrared reflectance simulations identify a highly conductive ZnO interface layer (thicknesses in the range of ≈ 10-29 nm for annealing temperatures ≥ 800 °C). The highly degenerate interface layers with temperature-independent carrier concentration and mobility significantly influence the electronic and optical properties of the BZO films. A parallel conduction model is employed to determine the carrier concentration and conductivity of the bulk and interface regions. The density-of-states-averaged effective mass of the conduction electrons for the interfaces is calculated to be in the range of 0.31 m0 and 0.67 m0. A conductivity as high as 1.4 × 10(3) S · cm(-1) is attained, corresponding to the carrier concentration n(Int) = 2.16 × 10(20) cm(-3) at the interface layers, and comparable to the highest conductivities achieved in highly doped ZnO. The origin of such a nanoscale degenerate interface layer is attributed to the counter-diffusion of Be and Zn, rendering a high accumulation of Zn interstitials and a giant reduction of charge-compensating defects. These observations provide a broad understanding of the thermodynamics and phase transformations in Be(x)Zn(1-x)O alloys for the application of highly conductive and transparent oxide-based devices and fabrication of their alloy nanostructures.

Keywords: BeZnO; atomic diffusion; defect engineering; degenerate interface; oxide alloys; phase transformation

Publication Types