Anomalous heavy doping in chemical-vapor-deposited titanium trisulfide nanostructures

Trichalcogenide semiconductors could provide a platform for quasi-one-dimensional electronic devices, on condition that their tunable doping capability is established. This work presents a synthetic strategy towards degenerately doped titanium trisulfide nanostructures that feature ultralow carrier activation barriers and exceptional ambient stability. The anomalous electrical conductivity of the synthesized nanostructures is revealed both experimentally and computationally to be associated with high-density S22- vacancies, which are generated spontaneously during the chemical vapor deposition process and act effectively as the electron dopants. These results hence portend the tantalizing possibility of constructing nanoscale electronics with defect-engineered trichalcogenide semiconductors.