Advantage on Superconductivity of Heavily Boron-Doped (111) Diamond Films

TL;DR

This paper reports the highest superconducting transition temperatures achieved in boron-doped (111) diamond films, highlighting the advantage of this orientation over (100) films due to higher carrier concentration.

Contribution

It demonstrates that (111) diamond films exhibit significantly higher Tc than (100) films at similar boron doping levels, due to increased carrier concentration.

Findings

Tc(onset) of 11.4 K and Tc(offset) of 7.4 K achieved in (111) diamond films

(111) films have more than twice the Tc of (100) films at same doping

Tc correlates with boron content and exceeds the doping level due to higher carrier concentration

Abstract

The superconductivity transition temperatures Tc(onset) of 11.4 K and Tc(offset) of 7.4 K, which are the highest in diamond at present, are realized on homoepitaxially grown (111) diamond films with a high boron doping concentration of 8.4E21 cm-3 (4.7 atomic percent). Tc values of (111) diamond films are more than twice as high as those of (100) films at the equivalent boron concentration. The Tc of boron-doped (111) diamond increases as the boron content increases up to the maximum incorporated concentration and is agrees with the value estimated using McMillan's equation. The advantageous Tc for (111) diamond films is due to the higher carrier concentration which exceeds its boron concentration.