Energy band calculation of amorphous indium tin oxide films on polyethylene terephthalate substrate with indirect transition

Amorphous indium tin oxide films were grown on a polyethylene terephthalate substrate by RF-magnetron sputtering. The energy band, which contained not only the width of the optical band but also detailed information about the Fermi level (Ef) and mobility edge (Ec'), was calculated according to the theory of amorphous semiconductors with the experimental parameters of transmittance and electrical conductivity. Furthermore, the calculated energy band can be used to effectively explain both the variation of electrical conductivity and the weak absorption at the wavelength range of 750-800 nm in our experiment. An indirect transition was also clearly observed in our samples during the calculation of the optical energy band.