Raman Spectroscopy as an Effective Tool for Assessment of Structural Quality and Polymorphism of Gallium Oxide (GaO) Thin Films.

Raman spectroscopy, a versatile and nondestructive technique, was employed to develop a methodology for gallium oxide (GaO) phase detection and identification. This methodology combines experimental results with a comprehensive literature survey. The established Raman approach offers a powerful tool for nondestructively assessing phase purity and detecting secondary phases in GaO thin films.

Photoelectron Holographic Study for Atomic Site Occupancy for Si Dopants in Si-Doped κ-GaO(001).

We investigated atomic site occupancy for the Si dopant in Si-doped κ-GaO(001) using photoelectron spectroscopy (PES) and photoelectron holography (PEH). From PES and PEH, we found that the Si dopant had one chemical state, and three types of inequivalent Si substitutional sites (Si) were formed. The ratios for the inequivalent tetrahedral, pentahedral, and octahedral Si sites were estimated to be 55.

Structural and Photoelectronic Properties of κ-GaO Thin Films Grown on Polycrystalline Diamond Substrates.

Orthorhombic κ-GaO thin films were grown for the first time on polycrystalline diamond free-standing substrates by metal-organic vapor phase epitaxy at a temperature of 650 °C. Structural, morphological, electrical, and photoelectronic properties of the obtained heterostructures were evaluated by optical microscopy, X-ray diffraction, current-voltage measurements, and spectral photoconductivity, respectively. Results show that a very slow cooling, performed at low pressure (100 mbar) under a controlled He flow soon after the growth process, is mandatory to improve the quality of the κ-GaO epitaxial thin film, ensuring a good adhesion to the diamond substrate, an optimal morphology, and a lower density of electrically active defects.

Interfacial Properties of the SnO/κ-GaO p-n Heterojunction: A Case of Subsurface Doping Density Reduction via Thermal Treatment in κ-GaO.

The interfacial properties of a planar SnO/κ-GaO p-n heterojunction have been investigated by capacitance-voltage (-) measurements following a methodological approach that allows consideration of significant combined series resistance and parallel leakage effects. Single-frequency measurements were carried out in both series- and parallel-model measurement configurations and then compared to the dual-frequency approach, which permits us to evaluate the depletion capacitance of diode independently of leakage conductance and series resistance. It was found that in the bias region, where the dissipation factor was low enough, they give the same results and provide reliable experimental - data.