【Member Papers】Research team from the Xidian University High-quality crystalline NiO/β-Ga₂O₃ p–n heterojunctions grown by the low-cost and vacuum-free mist-CVD for device applications

      Researchers from the Xidian University have published a dissertation titled "High-quality crystalline NiO/β-Ga₂O₃ p–n heterojunctions grown by the low-cost and vacuum-free mist-CVD for device applications " in Science China Materials.

Abstract

      Gallium oxide (Ga₂O₃) p–n heterojunctions play an important role in addressing the difficulties in Ga₂O₃ p-type doping. Therefore, an efficient and economical fabrication method needs to be established to create single-crystal Ga₂O₃ heterojunctions for device applications. In this work, we successfully achieved epitaxial growth of single-crystal nickel oxide (NiO) and β-Ga₂O₃ heterojunctions based on the low-cost and vacuum-free mist chemical-vapor deposition. The full width at half maximum of the X-ray diffraction rocking curves of NiO (111) and β-Ga₂O₃ (−201) reached 0.077° and 0.807°, respectively. The energy band between NiO and β-Ga₂O₃ has a Type II heterojunction. Finally, we prepared a quasi-vertical diode based on the NiO/β-Ga₂O₃ heterojunction, which exhibits obvious rectification characteristics of the p–n junction and provides a reverse breakdown voltage of 117 V. This work proposes a low-cost fabrication method for β-Ga₂O₃ p–n heterojunctions.

Figure 1 (a) UV–vis transmittance spectra of the grown Ga₂O₃ and NiO (5% LiOH incorporated in the NiO precursor solution; in this study, it is uniformly labeled as NiO) film on sapphire. The inset in (a) is the Tauc plot for the NiO and Ga₂O₃ films. (b) XRD spectrum of the NiO/β-Ga₂O₃ heterojunction structure film. The XRD rocking curves of the (c) (−201) and (d) (−402) peaks of β-Ga₂O₃. The XRD rocking curves of the (e) (111) peak of NiO.

Figure 2 (a) Cross-sectional TEM image of the β-Ga₂O₃/NiO/sapphire interface at low magnification. (b–f) TEM-EDX mappings of Ni, Ga, Cl, C, and O. Cross-sectional TEM images of the (g) NiO/sapphire and (h) β-Ga₂O₃/NiO interfaces at high magnification.

Original link:https://doi.org/10.1007/s40843-023-2801-2