Prof Yen-Hung Lin

Abstract:

In the last decade, metal oxides have emerged as a fascinating class of electronic material, exhibiting a wide range of unique and technologically relevant characteristics. For example, thin-film transistors formed from amorphous or polycrystalline metal oxide semiconductors offer the promise of low-cost, large-area, and flexible electronics, exhibiting performances comparable to or in excess of incumbent silicon-based technologies. Atomically flat interfaces between otherwise insulating or semiconducting complex oxides, are also found to be highly conducting, displaying 2-dimensional (2D) charge transport properties, strong correlations, and even superconductivity. Field-effect devices employing such carefully engineered interfaces are hoped to one day compete with traditional group IV or III-V semiconductors for use in the next-generation of high-performance electronics. In this Concept article we provide an overview of the different metal oxide transistor technologies and potential future research directions. In particular, we look at the recent reports of multilayer oxide thin-film transistors and the possibility of 2D electron transport in these disordered/polycrystalline systems and discuss the potential of the technology for applications in large-area electronics.

Abstract:

High mobility thin-film transistor technologies that can be implemented using simple and inexpensive fabrication methods are in great demand because of their applicability in a wide range of emerging optoelectronics. Here, a novel concept of thin-film transistors is reported that exploits the enhanced electron transport properties of low-dimensional polycrystalline heterojunctions and quasi-superlattices (QSLs) consisting of alternating layers of In₂O₃, Ga₂O_3, and ZnO grown by sequential spin casting of different precursors in air at low temperatures (180-200 °C). Optimized prototype QSL transistors exhibit band-like transport with electron mobilities approximately a tenfold greater (25-45 cm² V^-1 s^-1) than single oxide devices (typically 2-5 cm² V^-1 s^-1). Based on temperature-dependent electron transport and capacitance-voltage measurements, it is argued that the enhanced performance arises from the presence of quasi 2D electron gas-like systems formed at the carefully engineered oxide heterointerfaces. The QSL transistor concept proposed here can in principle extend to a range of other oxide material systems and deposition methods (sputtering, atomic layer deposition, spray pyrolysis, roll-to-roll, etc.) and can be seen as an extremely promising technology for application in next-generation large area optoelectronics such as ultrahigh definition optical displays and large-area microelectronics where high performance is a key requirement.

Abstract:

We report on metal oxide superlattice systems grown from solution and their use in high electron mobility transistors. On the basis of temperature-dependent electron transport measurements and carrier distribution evaluation, we argue that the enhanced performance arises from the presence of 2-dimensional electron gaslike systems formed at the oxide-oxide heterointerfaces.

Abstract:

We report on metal oxide superiattice systems grown from solution and their use in high electron mobility transistors. On the basis of temperature-dependent electron transport measurements and carrier distribution evaluation, we argue that the enhanced performance arises from the presence of 2-dimensional electron gas-like systems formed at the oxide-oxide heterointerfaces.