AbstractGallium oxide is a promising semiconductor with great potential for efficient power electronics due to its ultra-wide band gap and high breakdown electric field. Optimization of halide vapor phase epitaxy growth of heteroepitaxial $$\upbeta$$
β
-Ga2O3 layers is demonstrated using a simulation model to predict the distribution of the ratio of gallium to oxygen precursors inside the reactor chamber. The best structural quality is obtained for layers grown at 825–850 °C and with a III/VI precursor ratio of 0.2. Although the structural and optical properties are similar, the surface morphology is more deteriorated for the $$\upbeta$$
β
-Ga2O3 layers grown on 5 degree off-axis sapphire substrates compared to on-axis samples even for optimized process parameters. Cathodoluminescence with a peak at 3.3 eV is typical for unintentionally doped n-type $$\upbeta$$
β
-Ga2O3 and shows the appearance of additional emissions in blue and green region at ~ 3.0, ~ 2.8, ~ 2.6 and ~ 2.4 eV, especially when the growth temperatures is lowered to 800–825 °C. Estimation of the band gap energy to ~ 4.65 eV from absorption indicates a high density of vacancy defects.
ABSTRACTWe present experimental evidence for the spontaneous breaking of cubic symmetry in the band structure of films of Ga0 52 1n0 48P grown by organomeltallic vapor phase epitaxy on (100) GaAs substrates. We show how this effect is related to the spontaneous ordering of the alloy, and its correlation with the anomalous lowering of the band-gap observed in these films.
AbstractZincblende ZnxCdl−xSe alloys were grown on (001) InP by organometallic vapor phase epitaxy (OMVPE) using various VI / H precursor flow ratios, ranging from 0.95 to 12, at a temperature of 420°C. Spatial distribution of luminescent centers in the epilayer was characterized by cathodoluminescence (CL) spectroscopy and imaging. Both near band-gap (NBE) and deep level (DLE) emissions were observed in the spectra, with the width of the NBE peak increases with the VI / II flow ratio. Monochromatic CL images showed that the broadening of the NBE peak has its origin in the spatial inhomogeneity of the luminescent centers of the epilayer. Extended defects responsible for the DLE was only found in pyramidal hillocks seen in the CL images. The density of these defects was found to increase with the VI / I1 flow ratio.
Development of β-Ga2O3 layers growth on sapphire substrates employing modeling of precursors ratio in halide vapor phase epitaxy reactor