Enhanced p-type conduction of B-doped nanocrystalline diamond films by high temperature annealing

Abstract

We report the enhanced p-type conduction with Hall mobility of 53.3 cm2 V−1 s−1 in B-doped nanocrystalline diamond (NCD) films by 1000 °C annealing. High resolution transmission electronic microscopy, uv, and visible Raman spectroscopy measurements show that a part of amorphous carbon grain boundaries (GBs) transforms to diamond phase, which increases the opportunity of boron atoms located at the GBs to enter into the nano-diamond grains. This phase transition doping is confirmed by the secondary ion mass spectrum depth profile results that the concentration of B atoms in nano-diamond grains increases after 1000 °C annealing. It is also observed that 1000 °C annealing improves the lattice perfection, reduces the internal stress, decreases the amount of trans-polyacetylene, and increases the number or size of aromatic rings in the sp2-bonded carbon cluster in B-doped NCD films. These give the contributions to improve the electrical properties of 1000 °C annealed B-doped NCD films.