Journal of Korean Ophthalmic Optics Society (한국안광학회지)

The Korean Ophthalmic Optics Society (한국안광학회)
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Instability of Electric Characteristics in Hydrogenated Amorphous Carbon

수소화된 비정질 탄소박막에서 전기적 특성의 불안정성

  • Kang, Sung Soo (Department of Ophthalmic Optics, Taegu PolyTechnic College) ;
  • Lee, Won Jin (Department of Ophthalmic Optics, Taegu PolyTechnic College)
  • 강성수 (대구산업정보대학 안경광학과) ;
  • 이원진 (대구산업정보대학 안경광학과)
  • Received : 19991131
  • Published : 1999.12.31
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Abstract

This paper presents experimental results on the electrical properties of hydrogenated amorphous carbon films(a-C:H) prepared by PECVD. DC conductance of a-C:H was measured as a function of temperatures in the range of 100 to 423K. We studied two a-C:H films: one was well explained by the Mott's Variable Range Hopping(VRH) rule, but the other sample did not follow it. However, the conduction data of second sample were well fitted to Shimakawa's Multi-Phonon Hopping(MPH) model according to which conductivity is proportional to $T^M$ with m=15-17. but, in our samples, m was 10-12. Also a-C:H showed several bias effects like relaxation of conductance, bias-dependent conductance and the change of conductance slope in 1n(${\sigma}{\sqrt{T}}$) vs. $T^{1/4}$ plot. In this study we interpret these data by bias-dependent detrapping model.

PECVD 방법에 의하여 제작된 수소화된 비정질 탄소박막에서 측정 전압에 따른 전기전도도의 급격한 변화와 시간에 따른 전류의 이완 현상을 관측하였다. 이 현상은 Hammer 등에 의해 four-probe 측정과 샌드위치형 전극 시료에 대해서 측정한 것과 동일하였다. 본 연구에서는 "높은 전압에서 전자가 트랩에 포획될 확률이 작아진다"는 가정 하에서 정성적이지만 전기전도도의 측정 전압 의존에 관한 세 가지 현상이 비교적 잘 설명됨을 제시하였다.

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