High-mobility material research for thin-film transistor with amorphous thallium–zinc–tin oxide semiconductor

Abstract

The applicability of thallium-zinc-tin oxide (TlZnSnO) as a channel material for a thin-film transistor (TFT) was investigated by first-principles simulation and cosputtering experiment with XZnSnO (X = Al, Ga or In). The electron effective mass (m*) of Tl 0.4 ZnSnO was simulated to be >0.153, which is much smaller than that of In 0.4 ZnSnO (0.246). An In 0.4 ZnSnO TFT exhibited a mobility (μ) of 32.0 cm 2 V %1 s %1 in the experiment; therefore, the Tl 0.4 ZnSnO TFT was expected to have a higher mobility of approximately 50 cm 2 V %1 s %1 following the relation (μ / 1/m*). Moreover, the Tl-related oxide semiconductor would provide better TFT stability because its oxide vacancy is more stable than that of an In-related oxide semiconductor.

Properties of TlZnSnO film fabricated via sputtering from TlZnSnO target

“…The PO 2 dependences of the optical bandgaps for conditions A-D are shown in figure 4. There is no significant difference between these results and the energy bandgaps simulated via the first-principles method for Tl content of under 1% [11].…”

“…The experimented (at 10 Pa) and simulated optical bandgaps are plotted in figure 5. The simulation method was explained in our previous work [11]. The linear fit indicating the approximately linear relationship between the Tl concentration and energy bandgap in TlZnSnO obtained from the simulation.…”

“…As this is the first trial of TlZnSnO film preparation, not only the electrical properties, optical properties, and atomic concentration of the resultant film are reported, but also the band structure. In this study, the optical properties of the TlZnSnO film was also estimated based on first-principles simulations which has been conducted in our previous work [11]. So, the measured results of the optical property are compared with the simulated results for TlZnSnO films with the varied Tl content.…”