Synthesis and properties of ZnO(Li) crystals
- Moscow State Transport Univ. (Russian Federation); and others
Dissolution of lithium in ZnO crystals (up to N{sub Li} {approx} 10{sup 19}cm{sup {minus}3}) has little or no effect on their structural perfection. The lithium dopant in ZnO may occupy interstices (Li{sub i}) or may substitute for the Zn site (Li{sub Zn}), acting, respectively, as a shallow donor with the ionization energy E{sub d} = 0.04 eV or as an acceptor with E{sub a}(optical){approx}1 eV (optical depth measured from the edge of the valence band) and the thermal depth Ea (thermal) = 0.2 - 0.4 eV. In an unexcited crystal, the substitutional lithium ion is coordinated by four oxygen ions 0 inch, creating the (Li{sup +}{sub Zn}-0 inch) foot complex. The corresponding lithium states are denoted by Li{sup foot}{sub Zn}. These defects become paramagnetic (Li{sup x}{sub Zn} or, in a more complete notation, (Li{sup +}{sub Zn}-0 foot){sup x}) when a hole is trapped (or an electron is released) by one of the nearest neighbor oxygen ions. The resulting centers are responsible for the yellow-orange luminescence of Zn, O well studied using ESR under light illumination. There exist many contradictions in interpreting the electrical and optical properties of ZnO(Li) crystals. Most of these contradictions stem from the fact that in many cases inadequate attention is paid to prepararation conditions, to the presence of minority defects, as well as to the amphoteric nature of the lithium dopant, which governs the electrical conductivity of the host crystals. In the present work, we summarize our recent results on the synthesis of ZnO(Li) samples with preset often unique properties.
- OSTI ID:
- 244246
- Journal Information:
- Inorganic Materials, Vol. 31, Issue 10; Other Information: PBD: Oct 1995; TN: Translated from Neorganicheskie Materialy; 31: No. 10, 1364-1366(1995)
- Country of Publication:
- United States
- Language:
- English
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