중성자 조사한 ZnO 박막에 생성된 핵전환 불순물들에 대한 연구

A Study on Transmuted Impurity Atoms Formed in Neutron-Irradiated ZnO Thin Films

  • 발행 : 2002.07.01

초록

Transmuted impurity atoms formed in neutron-irradiated ZnO thin films were theoretically identified first and then experimentally confirmed by photoluminescence (PL). ZnO thin films grown by plasma-assisted molecular beam epitaxy were irradiated by neutron beam at room temperature. The ZnO films consist of eight constituent (Zn and O) isotropes, of which four are transmutable by neutron-irradiation; $^{64}$ , $^{68}$ Zn, $^{70}$ Zn and $^{18}$ O were expected to transmute into $^{65}$ Cu, $^{69}$ Ga, $^{71}$ Ga, and $^{19}$ F, respectively. The concentrations of these transmuted atoms were estimated in this study by considering natural abundance, neutron fluence and neutron cross section. The neutron-irradiated ZnO thin films were characterized by PL. In the PL spectra of the ZnO thin films, the Cu-related PL peaks were seen, but the Ga- or F-associated PL peaks were absent. This observation confirmed the existence of $^{65}$ Cu in the ZnO, but it could not do the formation of the other two. In this paper, the emission mechanism of Cu impurities is described and the reason for the absence of the Ga- or F-associated PL peaks is discussed as well.

키워드

참고문헌

  1. E. D. Wheeler, Jack L. Boone, J W. Farmer, H. R. Chandrasekhar, 'Neutron transmutation doping as an experimental probe for Ass, in ZnSe', Phys. Rev. B, Vol. 53, pp. 15617-15621, 1996 https://doi.org/10.1103/PhysRevB.53.15617
  2. Jian Liu, Pei-xuan Wang, 'Photoluminescence study of the defects induced by neutron irradiation and rapid annealing in semi-insulating GaAs', J. Appl. Phys., Vol. 86, pp. 764-767, 1999 https://doi.org/10.1063/1.370801
  3. A. A. Horns, B. Mari, 'Photolunescence of undoped and neutron-transmutation- doped InSe', J .Appl. Phys., Vol. 88, pp. 4654-4659, 2000 https://doi.org/10.1063/1.1308066
  4. K. Kuriyama, K. Ohbora, M. Okada, 'Photoluminescence from transmuted impurities in neutron- transmutation-doped semi-insulating GaP', Solid State Commun.. Vol. 113, pp. 415-418, 2000 https://doi.org/10.1016/S0038-1098(99)00499-8
  5. M. Coeck, N. Balcaen, T. Van Hoecke, B. Van Waeyenberge, D. Segers. C. Dauwe, C. Laermans, 'Defects in neutron transmutation doped silicon studied by positron annihilation lifetime measurements', J. Appl, Phys., Vol. 87, pp, 3674-3677, 2000 https://doi.org/10.1063/1.372398
  6. Firestone, B. Richard, 'Table of isotopes', 8th edition, Wiley-Interscience, New York, 1996
  7. H. J. Ko, Y. F. Chen, S. K. Hong, H. Wenisch, and T. Yao, 'Ga-doped ZnO films grown on GaN templates by plasma-assisted molecular-beam epitaxy', Appl. Phys. Lett. Vol. 77. pp. 3761-3763. 2000 https://doi.org/10.1063/1.1331089
  8. W. F. Wei, 'F' center in ZnO', Phys, Rev. B Vol. 15, pp. 2250-2253, 1977 https://doi.org/10.1103/PhysRevB.15.2250
  9. P. J. Dean, D. J. Robbins, S. G. Bishop, J. A. Savage and P. Porteous, 'The optical properties of copper in zinc oxide', J. Phys. C : Solid state Phys., Vol. 14, pp. 2847-2858, 1981 https://doi.org/10.1088/0022-3719/14/20/021
  10. D. J. Robbins, D. C. Herbert, P. J. Dean, 'The origin of the ${\alpha},\;{\beta}\;{\gamma}$ blue no-phonon transitions in ZnO: Cu-A deep-level problem', J. Phys. C : Solid state Phys., Vol. 14, pp. 2859-2870, 1981 https://doi.org/10.1088/0022-3719/14/20/022