A Study of the Growth of Single-Phase Mg0.5Zn0.5O Films for UV LED
Single-phase, high band gap energy Zn0.5Mg0.5O films were grown under oxygen pressure, using pulse laser deposition with a Zn0.5Mg0.5O target. Structural characterization studies revealed that the crystal structures of the ZnX-1MgXO films could be controlled via changes in the oxygen pressure. TEM analysis showed that the thickness of the deposited Zn1-xMgxO thin films was 50–75 nm. As the oxygen pressure increased, we found that one axis of the crystals did not show a very significant increase in the crystallization compared with that observed at low oxygen pressure. The X-ray diffraction peak intensity for the hexagonal-ZnMgO (002) plane increased relative to that for the cubic-ZnMgO (111) plane. The corresponding c-axis of the h-ZnMgO lattice constant increased from 5.141 to 5.148 Å, and the a-axis of the c-ZnMgO lattice constant decreased from 4.255 to 4.250 Å. EDX analysis showed that the Mg content in the mixed-phase ZnMgO films decreased significantly, from 54.25 to 46.96 at.%. As the oxygen pressure was increased from 100 to 150 mTorr, the absorption edge red-shifted from 3.96 to 3.81 eV; however, a film grown at the highest oxygen pressure tested here (200 mTorr).
Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1093842Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1757
 V. Srikantand D.R. Clarke, "On the optical band gap of Zinc oxide,”J. Appl. Phys. Vol. 83, pp. 5447-5451, 1998.
 P. Bhattacharya, R.R. Das, and R.S. Katiyar, "Fabrication of stable wide-band-gap ZnO/MgO multilayer thin films,”Appl. Phys. Lett. Vol. 83, pp. 2010-2012, 2003.
 M.H. Liang, Y.T. Ho, W.L. Wang, C.Y. Peng, and L. Chang, "Growth of ZnMgO/ZnO films on r-plane sapphires by pulsed laser deposition,’J. Crystal Growth Vol. 310, pp.1847-1852, 2008.
 I. Takeuchi, W. Yang, K.S. Chang, M.A. Aronova, T. Venkatesan, R.D. Vispute, and L.A. Bendersky,"Monolithic multichannel ultraviolet detector arrays and continuous phase evolution in MgZnOcompositin spreads,” J. Appl. Phys. Vol. 94, pp. 7336-7340, 2003.
 Y. Chen, H.J. Ko, S.K. Hong, and T. Yao, "Layer by layer growth of ZnOepilayer on Al2O3(0001) by using a MgO buffer layer,”Appl. Phys. Lett. Vol. 76, pp.559-561, 2000.
 A. Ohtomo, M. Kawasaki, T. Koida, K. Masubuchi, H. Koinuma, Y. Sakurai, Y. Yoshida, T. Yasuda, and Y. Segawa,"MgZnO as a II-V wideband gap semiconductor alloy,” Appl. Phys. Lett. Vol. 72 pp. 2466-2468, 1998.
 C.Y. Liu, H.Y. Xu, L. Wang, X.H. Li, and Y.C. Liu, "Pulse laser deposition of high Mg-content MgZnO films: Effects of substrate and oxygen pressure,”J. Appl. Phys. Vol. 106, pp. 073518-1-073518-4, 2009.
 Z.G. Ju, C.X. Shan, D.Y. Jiang, J.Y. Zhang, B. Yao, D.X. Zhao, D.Z. Shen, and X.W. Fan, "MgZnO based photodetectors covering the whole solar-blind spectrum range,”Appl. Phys. Lett. Vol. 93, pp. 173505-1-173505-3, 2008.
 B.P. Zhang, N.T. Binh, K. Wakatsuki, C.Y. Liu, Y. Segawa, and N. Usami, "Growth of ZnO/ZnMgO quantum wells on sapphire substrates and observation of the two-dimensional confinement effect,” Appl. Phys. Lett. Vol. 86, pp. 032105-1-032105-3, 2005.
 J. Z, Chen, C-H. Li, and I-C. Cheng, "Phase transition of room temperature RF-sputtered ZnO/MgZnO multilayer thin films after thermal annealing,”Thin Solid Films Vol.520, pp.1918-1923, 2012.
 Z. Vashaei, T. Minegishi, H. Suzuki, T. Hanada, M.W. Cho, T. Yao, and A. Setiawan,"Structure variation of cubic and hexagonal MgZnO layer grown on MgO(111)/c-sapphire,”J. Appl. Phys. Vol. 98, pp. 054911-1-054911-4, 2005.
 X. Chen and J. Kang,"The structural properties of wurtzite and rocksalt MgZnO,”Semicond. Sci. Technol.Vol. 23, pp. 025008, 2008.
 A. Kaushal and D. Kaur,"Effect of Mg content on the structural, electrical and optical properties of ZnMgO nanocomposite thin films,”Solar Energy Materials & Solar Cells Vol. 93 pp. 193-198, 2009.