Epitaxial growth of spinel Cr₂MnO₄ thin films on Ga₂O₃ for PN heterojunctions

The development of power devices relies on efficient, well-matched p- and n-type semiconductors. β-Ga₂O₃ is a widely studied candidate for n-type semiconductor applications, and its effectiveness in p-n heterojunctions has been established. However, identifying a suitable p-type counterpart for epitaxial growth is challenging due to the complex monoclinic crystal structure of β-Ga₂O₃. In this study, we deposited high-quality epitaxial Cr₂MnO₄ thin films on (-201)-oriented β-Ga₂O₃ substrates using radio-frequency sputter beam epitaxy. The films were used to fabricate p-n heterojunctions comprising p-Cr₂MnO₄/n-Ga₂O₃. The diodes exhibited good rectifying I-V characteristics with turn-on voltage of 0.5 – 1 V and rectifying ratio (I_F/I_R) greater than 10⁷ at ±5 V. We will present and discuss the optimization of the growth process as well as the rectifying behavior of the fabricated diodes.