Electrical Transport and Optical Properties of Hydrogen-Deficient YH 2 Films

Masamichi Sakai, Toru Kontani, Osamu Nakamura, Keishi Takeyama, Yoshiya Uwatoko, Yoshihisa Obi, Koki Takanashi

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12 Citations (Scopus)

Abstract

We have investigated electron transport characteristics of a hydrogen-deficient dihydride of yttrium YH2-3 (-0.3 < & δ < 0.05) focusing particularly on the effect of hydrogen deficiency on carrier relaxation time. At room- and low-temperatures, dc-specific resistivities obtained from electrical measurements show minimum values when hydrogen-deficient quantity δ is approximately -0.1. Optical conductivities were obtained from reflectance measurements by the Kramers-Knonig transformation. When & is changed, the carrier scattering rate determined from the optical conductivity shows a behavior similar to those of dc resistivities. Not only the carrier scattering rate but also a band-gap energy E0 associated with a Γ225 transition is influenced by the hydrogen deficiency; E0 shows a maximum value as δ is about -0.1. Hall coefficients are found to be positive but fairly small (∼10-11 m3/C), indicating that electrons as well as holes presumably contribute to electric conduction in YH2+δ.

Original languageEnglish
Pages (from-to)681-687
Number of pages7
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume43
Issue number2
DOIs
Publication statusPublished - 2004 Feb

Keywords

  • Dihydride yttrium
  • Electrical resistivity
  • Hall coefficient
  • Hydrogen vacancy
  • Optical conductivity
  • Relaxation time
  • YH

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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