Narrow-gap Semiconducting Superhard Amorphous Carbon with Superior Toughness

TL;DR

This study reports the synthesis of semiconducting amorphous carbon from fullerene under high pressure, revealing its unique structure, superhardness, and toughness, with potential optoelectronic applications beyond diamond and graphene.

Contribution

It introduces a reproducible high-pressure method to produce semiconducting amorphous carbon with superior properties and provides a detailed transformation model for future nanocarbon synthesis.

Findings

Amorphous carbon exhibits bandgaps of 0.1-0.3 eV.

Material shows isotropic superhardness and superior toughness.

Transformation mechanism elucidated through comprehensive characterization.

Abstract

New carbon forms exhibiting extraordinary physico-chemical properties can be generated from nanostructured precursors under extreme pressure. Nevertheless, synthesis of such fascinating materials is often not well understood that results, as is the case of C60 precursor, in irreproducibility of the results and impeding further progress in the materials design. Here the semiconducting amorphous carbon having bandgaps of 0.1-0.3 eV and the advantages of isotropic superhardness and superior toughness over single-crystal diamond and inorganic glasses are produced from transformation of fullerene at high pressure and moderate temperatures. A systematic investigation of the structure and bonding evolution was carried out by using rich arsenal of complimentary characterization methods, which helps to build a model of the transformation that can be used in further high p,T synthesis of novel nanocarbon systems for advanced applications. The produced amorphous carbon materials have the potential of demanding optoelectronic applications that diamond and graphene cannot achieve