Figure 3
From: Dual active layer a-IGZO TFT via homogeneous conductive layer formation by photochemical H-doping
Chemical binding states, bond fraction evolutions of XPS spectra, and UV/air photochemical H-doping scheme. (a) O1s and Zn2p3/2 XPS spectra of the as-deposited a-IGZO with different UV/air exposure time and their Gaussian peak deconvolution. In the O1s XPS spectra, two chemical binding states were resolved: (1) O2--M fully oxidized states (530.5 eV) and (2) OH (532 eV). For Zn ions, three types of binding states were extracted in each metal ion: (1) O-deficient Zn1+ equivalent to O-vacancy, (2) Zn-O in the fully oxidized state (Zn2+), and (3) Zn bonded to OH group. The bond fraction evolutions of (b) Zn-OH in Zn2p and OH in O1s and (c) In-OH [1]/[2] ([1] is for low and [2] is for high binding energy) and Ga-OH [1]/[2] as a function of UV exposure time. (d) Scheme of UV/air photochemical H-doping in a-IGZO.