Effect Of Zinc Oxide RF Sputtering Pressure on the Structural and Optical Properties of ZnO/PEDOT:PSS Inorganic/Organic Heterojunction

Document Type : Articles

Authors

Department of Electrical Engineering, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

Zinc oxide nanostructures are deposited on glass substrates in the presence
of oxygen reactive gas at room temperature using the radio frequency magnetron
sputtering technique. In this research, the effects of zinc oxide sputtering pressure on the
nanostructure properties of the deposited layer are investigated. The deposition pressure
varies from 7.5 to 20.5 mTorr. AFM results show that with an increase in the deposition
pressure, the grain size increases and the surface roughness decreases. The energy gap
measured for the zinc oxide layers deposited at the pressures of 7.5, 14 and 20.5 mTorr
was 3.26, 3.18, and 3.19 eV, respectively. In order to investigate the junction between
zinc oxide and poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS),
a polymeric layer of thickness of 50 nm is deposited on a 300 nm zinc oxide layer by
spin coating technique. The dark I-V characteristics indicate that the reverse saturation
current density is 1.82 10-6, 1.96 10-7 and 7.58 10-8 A/cm2 for the deposition
pressures of 7.5, 14, and 20.5 mTorr, respectively. By increasing the deposition pressure
the ideality factor of the resulting Schottky barrier dropped from 3.4 to 1.7. The
effective Schottky barrier height of 0.73, 0.78, and 0.81 eV was obtained for the same
order of deposition pressures. It was found that the highest optical response could be
obtained for the samples deposited at the deposition pressure of 14 mTorr..

Keywords

References

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