Oxide semiconductors have garnered significant attention in recent years due to their wide bandgaps, high transparency, and high breakdown fields. These characteristics make them ideal candidates for next-generation high-power and frequency electronic devices. To fully leverage these properties, epitaxial growth is essential as it enables the formation of highly crystalline, defect-minimized thin films for the performance and reliability of devices. Among the various epitaxial deposition techniques, Mist Chemical Vapor Deposition (Mist-CVD) has emerged as a promising method for synthesizing high-quality films. Mist-CVD operates under atmospheric pressure and utilizes an ultrasonically generated mist of precursor solutions, allowing for uniform film growth at relatively low substrate temperatures. This method offers precise compositional control, scalability, and compatibility with flexible substrates. In this work, we explore the synthesis of various oxide semiconductors including β-Ga2O3, α-Ga2O3, NiO, and r-GeO2 using Mist-CVD. Structural, optical, and electrical characterizations confirm the feasibility of this technique in producing epitaxial and conductive films. To achieve controlled n-type doping in homoepitaxial β-Ga2O3, varying concentrations of an organic silicon precursor were employed, yielding carrier concentrations in the range of 10^18 to 10^19 cm−3 with peak room temperature mobilities reaching 65 cm2V−1s−1. Since p-type doping in Ga2O3 remains a major challenge due to its intrinsically flat valence band, we fabricated heterojunction p–n devices by integrating p-type NiO with Ga2O3. Heteroepitaxial growth of high-quality p-type NiO thin films was carried out on sapphire, MgO, α-Ga2O3, and β-Ga2O3 substrates, achieving a growth rate of approximately 5.3 nm/min at 500°C. For p-type conductivity, Li doping was introduced with 10% Li concentration precursor, achieving a resistivity as low as 0.8 Ω·cm and carrier densities as high as 10^20 cm−3. The quality of the epitaxial NiO films was confirmed by X-Ray Rocking curve (XRC) with FWHM as low as ∼15 arcsec. With increasing growth temperature, the conductivity improved due to higher carrier densities. A selective wet etch using a 1:1 HCl:DI at 50°C was developed for NiO, with an etch rate of 2.6 nm/min, enabling both lateral and vertical device architectures. To demonstrate device architectures, we developed epitaxy of α-Ga2O3 on sapphire, achieving XRC of 790 arcsec. On these α-Ga2O3 films, a temperature-dependent study was performed on Li-doped NiO to identify conditions for single-phase NiO deposition below 600°C; the thermal stability of α-Ga2O3 is compromised at higher temperatures. This optimization facilitated the in situ growth of NiO/α-Ga2O3 heterojunctions at 400°C, showing the potential of Li-doped NiO to serve as a robust p-type layer for Ga2O3-based heterojunction devices. While NiO/Ga2O3 heterojunctions offer a promising route to overcoming the p-type doping limitations of Ga2O3, the search continues for alternative ultrawide bandgap(UWBG) materials with more balanced electronic properties. In this context, rutile GeO2 has emerged as a compelling candidate due to its wide bandgap (∼4.7eV), high dielectric constant, and predicted ambipolar doping potential. We investigated epitaxial growth of rutile GeO2 on (001) TiO2 substrates. XRD and AFM analysis confirmed phase-pure growth of small crystallites. As-grown films, however, were mostly soluble in water, indicating that most of the deposition was amorphous. Further research into seed layers, or graded nucleation strategies, will be essential to enable the growth of high-quality epitaxial GeO2 films suitable for electronic applications.