Supplemental Information
Dual-Active-Layers a-IGZO TFT via Homogeneous Conductive Layer
Formation by Photochemical H-doping
Seung-Ki Jeong, Myeong-Ho Kim, Sang-Yeon Lee, Hyungtak Seo and Duck-Kyun Choi
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10
20
16
-3
10
15
19
10
18
10
17
14
2
10
Hall Mobility (cm /Vsec)
Carrier Concentration (cm )
1. Time dependent doping stability test
carrier concentration
hall mobility
0
1
2
3
Time (Week)
4
13
5
Fig. S1. Hall measurement results (carrier concentration and hall mobility) as a function
of air aging-time. The a-IGZO/glass samples was maintained in the lab air since fabricated.
No significant changes in electrical parameters such as carrier concentration and hall mobility
was found even after 4 week air aging. This confirms that H doping by UV irradiation is
permanent and not due to the transient photocurrent, which is typically subject to several hr
recovery due to photocarrier detrapping from defect states.
1
2. XPS data of In3d and Ga2p
In3d
Ga2p
XPS Intensity (Arb. Unit)
UV 4hr
UV 2hr
UV 1hr
As-dep
In-OH [1]
In-OH [2]
In
3+
In
448
446
444
2+
Ga
Ga-OH [1]
Fa-OH [2]
442 1120
3+
Ga
2+
1115
Binding Energy (eV)
Fig. S2. In3d and Ga2p XPS data of the as-deposited and UV-exposed a-IGZO with
Gaussian peak deconvolution. Similar to the Zn ion, three types of binding states were
observed in each metal ion: (1) O-deficient In2+ and Ga2+ equivalent to the O-vacancy; (2) Inand Ga-O in the full oxidation state (In3+ and Ga3+); and (3) OH-related In/Ga bond (denoted
as In/Ga-OH [1] and In/Ga-OH [2] or possibly, In/Ga-O-OH).
2
3.
Absorption data of a-IGZO before and after UV-irradiation
As-dep
UV 1hr
UV 2hr
UV 4hr
5
-1
Absroption Coefficient (x10 cm )
3
2
0.5
0.4
As-dep
UV 1hr
UV 2hr
UV 4hr
0.3
0.2
1
0.1
0.0
3.0 3.2 3.4 3.6 3.8 4.0
Onset: 3.4 eV
0
3
4
5
6
Photon Energy(eV)
Fig. S3. Absorption coefficient spectra for the as-deposited and UV-irradiated a-IGZO
taken by spectroscopic ellipsometry analysis. The inset figure shows the magnified spectra
at 3~4 eV of photo energy. All samples reveals the absorption onset at ~ 3.4 eV and no
significant change in typical absorption edge. This data suggests UV-irradiation does not
incur the bulk optical properties in consistent with XPS results showing the strong H-doping
effect only at the surface region.
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