Modulation of electron transportation in amorphous and polycrystalline indium–zinc-oxide films grown by pulse laser deposition

Abstract Amorphous and polycrystalline indium–zinc-oxide (IZO) transparent conductive films have been grown by pulsed laser deposition (PLD) technique using O 2 and Ar as background gas, respectively. The evolution of surface morphology and crystalline structure of the IZO films have been discussed in the frame of the kinetic molecular theory by considering the different kinetic energy loss and the surface migration of impinging particles in Ar and O 2 atmosphere, respectively. Hall measurements show that for amorphous IZO films the highest electron mobility can be as high as 51 cm 2 /Vs with the electron concentrations (N e ) being 4.0 × 10 19 cm − 3 and the resistivity being 3.1 × 10 − 3 Ω cm. Temperature dependent Hall measurements indicate that when N e is 19 cm − 3 the dominant scattering mechanism is defect scattering, when N e is in the range of 10 19 –10 20 cm − 3 both the defects and the ionized impurity contribute to the carrier scatterings, and when N e is > 3.1 × 10 20 cm − 3 the formation of a non-parabolic conduction band in IZO films plays the most important role in the carrier scattering. The variation of the optical band gaps in IZO films with N e was addressed by taking account of both the Burstein–Moss shift and the band-gap-narrowing effects. Additionally, all the amorphous IZO films are highly transparent (transmission > 85%) in the visible spectrum, which makes the IZO films suitable for transparent conducting applications.