Hydrogen Influence on the Electrical, Optical and Chemical Properties of Aluminum
Gallium-doped Zinc Oxide Film Deposited by Facing Target Sputtering
Soo Ho Cho, Hye Young Jang, Sang Ho Kim
School of Energy, Materials and Chemical Engineering, Korea University of Technology
and Education
1600 Chungjeol-ro, Byeongcheon-myeon, Dongnam-gu, Cheonan-si, Chungnam,
31253, South Korea
E-mail
Aluminum gallium-doped zinc oxide (AGZO) film which is used for the solar cell electrode
must have a good corrosion resistance because the device should be exposed to the outside
environment. The corrosion resistance of the AGZO film was studied as a function of
hydrogen flowing rate during the face target sputtering (FTS). Face target sputtering is a very
unique thin film process which can reduce the ion bombardment during sputtering. Four
components AGZO film can have a bombardment free microstructure by FTS, and the
microstructure dependent corrosion behavior can be simplified without other effects. The
sheet resistance, optical transmittance and corrosion resistance of the AGZO films were
measured by using four point probe (and Hall measurement), spectrophotometer and
potentiostatic polarization test (and electrochemical impedance spectroscopy), respectively.
As the hydrogen content in the AGZO film increased, the sheet resistance decreased to
minimum and then increased again. The lower sheet resistance was obtained when it has a
better crystallinity with narrow full width half maximum of the X-ray diffraction peak and the
corrosion resistance showed a similar tendency. Discussion of the phenomena was related the
oxygen vacancies and grain boundary impurities measured by X-ray photoelectron
spectroscopy and energy dispersive spectroscopy of scanning electron microscopy.
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