Study on crystallization and oxygen vacancies of β-Ga2O3 powder synthesized from various alkalis

Controlling the crystallization of gallium oxide (Ga 2 O 3 ) crystal as well as intrinsic defects (oxygen vacancies) are crucial steps in obtaining high-quality material and elucidating how defects affect semiconductor properties . Gallium oxide hydroxide (GaOOH) was firstly synthesized via the reaction of gallium nitrate (Ga(NO 3 ) 3 ) with different alkalis (Urea, NH 3 ·H 2 O, Na 2 CO 3 and NaOH) using the precipitation technique. Then, Ga 2 O 3 powder was obtained by adding carbon powder as reducing agent at the calcination stage. The β-Ga 2 O 3 powder prepared by NH 3 ·H 2 O were found to have the best crystallization as analyzed by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Meanwhile, the photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) results combined with the first-principles calculation indicate that the Ga 2 O 3 powder made by NH 3 ·H 2 O also has the least intrinsic oxygen vacancies .