Figure 2
Band-gap and electrical conductivity of amorphous FDTO. (a) Direct and indirect bandgap obtained from Tauc plot for thin films of a-FDTO deposited at oxygen pressures ranging from 5 × 10−7 Torr to 1 × 10−3 Torr. (b) Schematic of band structure of a-FDTO film deposited at 2 × 10−6 Torr showing the bandgap, work function, and mobility edges and tail states at the conduction and valence bands. (c) Resistivity as a function of temperature from 3 K to 300 K for two a-FDTO films deposited at two different oxygen pressures. Both curves show semiconductor behavior. (d), (e) Fit of temperature dependent resistivity to (d) 3-D variable range hopping model, showing good fit for both a-FDTO films above 100 K, and (e) 1-D variable range hopping model showing good fit for both films below 100 K.
