Low Residual Carrier Density and High In-Grain Mobility in Polycrystalline Zn₃N₂ Films on a Glass Substrate

Abstract

We investigated the intrinsic physical properties of polycrystalline Zn3N2 thin films by suppressing donor impurities using the ultrahigh-vacuum sputtering technique. The residual carrier density was reduced to 4.4 × 1017 cm–3, resulting in a nondegenerate Zn3N2 thin film. In this film, we observed that grain boundary scattering had a significant effect on mobility, in contrast to previous reports on degenerate films. By fitting using the Seto model, the in-grain mobility reached 340 cm2 V–1 s–1, which is comparable to the mobility of epitaxial thin films, even though they were deposited at room temperature. Electric-double-layer transistors with nondegenerate Zn3N2 active layers were also examined to verify the potential as a transistor active layer material. The insights into trap density of polycrystalline Zn3N2 semiconductor in this report imply opportunities to explore high-performance flexible electronic devices.

Ultrastable Zn3N2 Thin Films via Integration of Amorphous GaN Protection Layers

“…[3] While group III-nitrides have thus far DOI: 10.1002/admi.202400214 attracted the most attention within this class of materials, group II-nitrides have increasingly emerged as interesting compound semiconductors with promising optical and electronic properties. For example, zinc nitride (Zn 3 N 2 ) is characterized by a direct bandgap of 1.0 eV, [4] enabling efficient absorption of solar radiation, as well as high electron mobilities (approaching 400 cm 2 V −1 s −1 ), [5] making it suitable as an active layer in thin-film transistor (TFT) [6] and photovoltaic devices. [7] Furthermore, it comprises only abundant elements and can be grown at considerably lower temperatures than, for example, most group IV and III-V semiconductors.…”