*3.2.2.2. Deep-ultraviolet assisted annealing (DUV)*

Much efforts have also been focused on the treatment of sol-gel films by photochemical activation using deep-ultraviolet (DUV) irradiation [36, 57–61]. When the as-deposited film is exposed to DUV irradiation, high-energy DUV photons induce photochemical cleavage of alkoxide groups and activate metal and oxygen atoms to facilitate M-O-M network formation (**Figure 5**, step 1, condensation). Further irradiation induces a gradual removal of oxygen and carbon (and, thereby, near-complete condensation) and a transition to a film densification (**Figure 5**, step 2, densification). This DUV technique is applicable to numerous AOS. The *μ* of the room temperature DUV-IGZO is as high as 14.0 cm<sup>2</sup> V−1 s−1.
