Superconductivity in heavily B-doped diamond layers deposited on highly oriented diamond films

Takahiro Muranaka, Koji Kobashi, Hirotaka Okabe, Takeshi Tachibana, Yoshihiro Yokota, Kazushi Hayashi, Nobuyuki Kawakami, Jun Akimitsu

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

We deposited a [100]-oriented B-doped diamond layer by three methods to clarify the effects of film morphology on the transition from metallic to superconducting diamond. Heavily B-doped [100]-oriented diamond layers were deposited on [first method] undoped polycrystalline diamond films with [111] faces, [second method] highly oriented undoped diamond (HOD) thin films with a pyramidal surface, and [third method] thick undoped HOD films with a pyramidal surface. We confirmed that the B-doped layer in the third method was oriented in the [100] direction by scanning electron microscopy (SEM). The highest transition temperatures were Tc(onset) = 5.0 K and T c(zero) = 3.1 K for the B-doped layer deposited on a thick HOD film with a pyramidal surface under a zero magnetic field. By contrast, T c(onset) was 4.1 K for a heavily B-doped diamond layer deposited on a thin HOD film with a pyramidal surface, and was 3.9 K for a heavily B-doped diamond layer deposited on an undoped polycrystalline diamond film. These differences in Tc for our samples are affected by disorder and effective hole-carrier doping in each sample. Using the third method, we successfully deposited a high-quality B-doped [100] layer in three steps: (first step) depositing a [100] HOD film on a Si [100] substrate, (second step) depositing an HOD film with a pyramidal surface, and (third step) depositing a [100]-oriented B-doped layer. The change in the electronic states due to the B-doping of diamond films and the film morphology were investigated by x-ray photoelectron spectroscopy (XPS) measurements and band calculations.

Original languageEnglish
Pages (from-to)1273-1281
Number of pages9
JournalDiamond and Related Materials
Volume20
Issue number9
DOIs
Publication statusPublished - Oct 1 2011
Externally publishedYes

Keywords

  • Akai-KKR
  • B-doped diamond
  • SEM
  • Superconductivity
  • XPS

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Chemistry(all)
  • Mechanical Engineering
  • Physics and Astronomy(all)
  • Materials Chemistry
  • Electrical and Electronic Engineering

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