Epitaxial Cr2MnO4 p–n heterojunction to (2¯01) β-Ga2O3 deposited via off-axis magnetron sputtering

We report the heteroepitaxial growth of spinel Cr2MnO4 thin films on (2¯01) β-Ga2O3 substrates via off-axis RF magnetron sputtering. Structural analysis confirms (111)-oriented epitaxial films with optimized growth at 950 °C. Fabricated Cr2MnO4/β-Ga2O3 vertical diodes exhibit rectifying behavior with high on/off ratios (∼108), turn-on voltages near 0.85 V, and low reverse leakage current. Transmission electron microscopy and atomic force microscopy analyses show the films exhibit a Stranski–Krastanov growth mode, with three-dimensional texturing of potential interest for device performance. Capacitance–voltage measurements reveal intrinsic p-type conductivity with carrier concentration ∼7 × 1017 cm−3. The results suggest that Cr2MnO4 may be a promising candidate for Ga2O3-based bipolar devices.