We deposited a -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 -oriented diamond layers were deposited on [first method] undoped polycrystalline diamond films with  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  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  layer in three steps: (first step) depositing a  HOD film on a Si  substrate, (second step) depositing an HOD film with a pyramidal surface, and (third step) depositing a -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.
- B-doped diamond
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Physics and Astronomy(all)
- Materials Chemistry
- Electrical and Electronic Engineering