Y2O3 spacer layer engineering for high mobility 2DEG heterostructure of MgZnO/CdZnO utilizing DIBS

Abstract

In this work, we investigate the effect of Y<inf>2</inf>O<inf>3</inf> spacer layer thickness on the two-dimensional electron gas mobility (μ) and sheet carrier density (n<inf>s</inf>) of a dual ion beam sputtering (DIBS)-grown MgZnO/CdZnO heterostructure. High-resolution transmission electron microscopy analyses reveal that a 200 nm thick Y<inf>2</inf>O<inf>3</inf> spacer layer significantly improves the crystallinity of the heterostructure. Hall measurements show enhanced electron mobility, increasing from 18.3 to 43.8 cm2 V−1 s−1 and a reduction in sheet carrier density from 7.31 × 1013 to 5 × 1013 cm−2, on increasing the Y<inf>2</inf>O<inf>3</inf> layer thickness from 50 to 200 nm. This highly efficient low cost DIBS heterostructure is suitable for high frequency and low power high-electron-mobility transistor device applications. © 2025 Elsevier B.V., All rights reserved.