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Growth and Electrical Properties of Spinel-type ZnCo2O4 Thin Films by Reactive Magnetron Sputtering

반응성 때려내기 방법에 의한 스피넬 형 ZnCo2O4 박막의 성장과 전기적 물성

  • Song, In-Chang (Department of Materials Science and Engineering, Chungnam National University) ;
  • Kim, Hyun-Jung (Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Sim, Jae-Ho (Department of Materials Science and Engineering, Chungnam National University) ;
  • Kim, Hyo-jin (Department of Materials Science and Engineering, Chungnam National University) ;
  • Kim, Do-jin (Department of Materials Science and Engineering, Chungnam National University) ;
  • Ihm, Young-Eon (Department of Materials Science and Engineering, Chungnam National University) ;
  • Choo, Woong-Kil (Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology)
  • 송인창 (충남대학교 재료공학과) ;
  • 김현중 (한국과학기술원 재료공학과) ;
  • 심재호 (충남대학교 재료공학과) ;
  • 김효진 (충남대학교 재료공학과) ;
  • 김도진 (충남대학교 재료공학과) ;
  • 임영언 (충남대학교 재료공학과) ;
  • 주웅길 (한국과학기술원 재료공학과)
  • Published : 2003.08.01

Abstract

We report the synthesis of cubic spinel $ZnCo_2$$O_4$thin films and the tunability of the conduction type by control of the oxygen partial pressure ratio. Zinc cobalt oxide films were grown on$ SiO_2$(200 nm)/Si substrates by reactive magnetron sputtering method using Zn and Co metal targets in a mixed Ar/$O_2$atmosphere. We found from X-ray diffraction measurements that the crystal structure of the zinc cobalt oxide films grown under an oxygen-rich condition (the $O_2$/Ar partial pressure ratio of 9/1) changes from wurtzite-type $Zn_{1-x}$ $Co_{X}$O to spinel-type $ZnCo_2$$O_4$with the increase of the Co/Zn sputtering ratio,$ D_{co}$ $D_{zn}$ . We noted that the above structural change accompanied by the variation of the majority electrical conduction type from n-type (electrons) to p-type (holes). For a fixed $D_{co}$ $D_{zn}$ / of 2.0 yielding homogeneous spinel-type $_2$O$ZnCo_4$films, the type of the majority carriers also varied, depending on the$ O_2$/Ar partial pressure ratio: p-type for an $O_2$-rich and n-type for an Ar-rich atmosphere. The maximum electron and hole concentrations for the Zn $Co_2$ $O_4$films were found to be 1.37${\times}$10$^{20}$ c $m^{-3}$ and 2.41${\times}$10$^{20}$ c $m^{-3}$ , respectively, with a mobility of about 0.2 $\textrm{cm}^2$/Vs and a high conductivity of about 1.8 Ω/$cm^{-1}$ /.

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