High-Quality Crystalline Nio/Β-Ga2o3 P-N Heterojunctions Grown by the Low-Cost, Vacuum-Free Mist-Cvd for Ga2o3 Device Application

Gallium oxide (Ga2O3) p-n heterojunction plays an important role in the background of the Ga2O3 p-type doping difficulty. To avoid the defects brought by polycrystalline or amorphous materials, it is urgently required to find an efficient and economical fabrication method to realize the single-crystal Ga2O3 heterojunctions for device applications. In this work, we have successfully achieved epitaxial growth of single-crystal nickel oxide (NiO) and β-Ga2O3 heterojunctions based on the low-cost, vacuum-free Mist chemical vapor deposition (Mist-CVD). The full width at half maximum (FWHM) of the XRD-rocking curves about NiO (111) and β-Ga2O3 (-201) achieved 0.077° and 0.807°, respectively. The energy offset of valence band maximum values between the NiO and β-Ga2O3 heterojunction is 1.24 eV, which results in the type-II heterojunction. It is also shown that incorporating LiOH in the NiO precursor solution can affect the properties of the NiO film. When the molar proportion of LiOH in NiO precursor solution is 5%, the NiO film shows the lowest resistance. Finally, we prepared a quasi-vertical diode based on the NiO/β-Ga2O3 heterojunction which showed the typical p-n junction characteristics and gave a reverse breakdown voltage of 117 V. Our work hopes to offer a low-cost fabricate method for β-Ga2O3 heterojunction p-n junctions.