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Degradation mechanisms of the aluminium doped zinc oxide front contact
Table 6.1 Degradation conditions for the ZnO:Al samples cells and the sample ab-
breviation used in this chapter.
Conditions Name
H 2 O H 2 O
H 2 O purged with CO 2 H 2 O/CO 2
H 2 O purged with O 2 H 2 O/O 2
H 2 O purged with N 2 H 2 O/N 2
H 2 O purged with compressed air H 2 O/air
CO 2 gas CO 2
O 2 gas O 2
Argon gas (glovebox) Argon
6.2.3 Characterisation of film properties
The samples in both experiments were characterised by a number of techniques
before, during and after degradation.
A PhysTech RH2010 Hall effect measurement tool, a Jandel Engineering Cylindrical
Probe four-point and a Dektak 8 advanced development profiler were used to
determine the electrical properties and the thickness of the film respectively. The
optical properties were determined by a Shimadzu UV-3600 UV-VIS-NIR, which allowed
analysis of the transmittance and reflectance of the ZnO:Al samples including the
glass. From these data, the absorption was calculated. A Leica Wild M400 macroscope
and a digital camera were used to determine the visual changes.
The morphological and structural properties of the films were determined by a FEI
Quanta 600 Scanning Electron Microscope (SEM) combined with Energy Dispersion
X-ray (EDX) EDAX Genesis 4000, and a Zeiss Orion plus Helium Ion Microscope (HIM)
with a Everhart-Thornley detector. The He ions had a voltage of 25kV with a current of
0.5 to 2 pA. A Philips X’pert 5068 powder diffractometer, equipped with a CuK source
α
o
(λ=0.154 nm) in the 5 to 95 2θ range with a step size of 0.02 was also used to deter-
o
o
mine the structural properties.
In the damp heat experiment, the grain sizes as described in the introduction have
been determined from Helium Ion Microscopy (HIM) images. This required additional
sample preparation of the ZnO:Al layers by helium etching. The active helium species
were introduced in the layer, causing the weaker spots of the layer, in this case the
grain boundaries, to crack.
181
Table 6.1 Degradation conditions for the ZnO:Al samples cells and the sample ab-
breviation used in this chapter.
Conditions Name
H 2 O H 2 O
H 2 O purged with CO 2 H 2 O/CO 2
H 2 O purged with O 2 H 2 O/O 2
H 2 O purged with N 2 H 2 O/N 2
H 2 O purged with compressed air H 2 O/air
CO 2 gas CO 2
O 2 gas O 2
Argon gas (glovebox) Argon
6.2.3 Characterisation of film properties
The samples in both experiments were characterised by a number of techniques
before, during and after degradation.
A PhysTech RH2010 Hall effect measurement tool, a Jandel Engineering Cylindrical
Probe four-point and a Dektak 8 advanced development profiler were used to
determine the electrical properties and the thickness of the film respectively. The
optical properties were determined by a Shimadzu UV-3600 UV-VIS-NIR, which allowed
analysis of the transmittance and reflectance of the ZnO:Al samples including the
glass. From these data, the absorption was calculated. A Leica Wild M400 macroscope
and a digital camera were used to determine the visual changes.
The morphological and structural properties of the films were determined by a FEI
Quanta 600 Scanning Electron Microscope (SEM) combined with Energy Dispersion
X-ray (EDX) EDAX Genesis 4000, and a Zeiss Orion plus Helium Ion Microscope (HIM)
with a Everhart-Thornley detector. The He ions had a voltage of 25kV with a current of
0.5 to 2 pA. A Philips X’pert 5068 powder diffractometer, equipped with a CuK source
α
o
(λ=0.154 nm) in the 5 to 95 2θ range with a step size of 0.02 was also used to deter-
o
o
mine the structural properties.
In the damp heat experiment, the grain sizes as described in the introduction have
been determined from Helium Ion Microscopy (HIM) images. This required additional
sample preparation of the ZnO:Al layers by helium etching. The active helium species
were introduced in the layer, causing the weaker spots of the layer, in this case the
grain boundaries, to crack.
181
