Halide Vapor Phase Epitaxy α‐ and ε‐Ga<sub>2</sub>O<sub>3</sub> Epitaxial Films Grown on Patterned Sapphire Substrates
Sevastian Shapenkov, О. Ф. Вывенко, Е. В. Убыйвовк, Oleg Medvedev, Georgiy Varygin, A. V. Chikiryaka, А. И. Печников, M. P. Scheglov, С. И. Степанов, В. И. Николаев
Abstract
The growth of Ga 2 O 3 films by halide vapor phase epitaxy on plain and cone‐shaped patterned sapphire substrates (PSS) is reported. The obtained specimens are characterized by X‐ray diffraction, transmission electron microscopy, cathodoluminescence, optical transmission spectroscopy, and current–voltage measurements. Both types of Ga 2 O 3 layers are of reasonably high crystal qualities; their physical properties, however, are very different. Under the same conditions, the growth on plain substrates results in a continuous α‐Ga 2 O 3 layer, whereas the growth on PSS produces a regular array of α‐Ga 2 O 3 columns on top of the sapphire cones with the space between them filled with ε‐Ga 2 O 3 . Ga 2 O 3 films grown on plain sapphire are insulating; in contrast, Ga 2 O 3 films grown on PSS are conducting. It is found that the conductivity of Ga 2 O 3 on PSS follows the Arrhenius law with the activation energy of 0.33 eV. New luminescent bands for α‐ and ε‐phases are found. Spectral components of the defect‐related luminescence for α‐ and ε‐ phases are identified.