Properties and prospects for non-crystalline carbons

The electronic properties of amorphous carbons (a-Cs) are reviewed in terms of their applications. The carrier mobility, doping and disorder have so far proved not good enough for applications. The defects have recently been identified, and this holds out potential to reduce the defect concentration. There are two types of disorder, sp2 cluster size and stress. It is now possible to characterise the bonding and sp2 configurations in detail, particularly by Raman. The disordered sp2 carbons are less studied, now, and hold future promise.