HfO2-based ferroelectric materials do not necessarily require high-temperature annealing for crystallization, making them attractive for applications in transparent electronic devices on plastic or glass substrate. In this study, (Hf,Zr)O2 (HZO) films prepared via non-heating sputtering are investigated and their application to ferroelectric-gate thin-film transistors (TFTs) is demonstrated. The internal tensile stress induced by (In,Sn)Ox (ITO) top-electrode deposition is found to promote the crystallization of HZO from the amorphous state to the ferroelectric phase. ITO/HZO (15-25 nm)/ITO capacitors prepared via the non-heating process exhibit ferroelectric hysteresis loops with remanent polarizations of 6–9 µC/cm2 and coercive fields of 0.6–1.1 MV/cm. Ferroelectric-gate TFTs with a 10-nm-thick ITO channel are also fabricated via the non-heating process. These TFTs show nonvolatile operation with an on/off ratio of ~10. These findings demonstrate the potential of HZO for transparent devices on substrates with low thermal resistance prepared via the non-heating process.