Edge Absorption of thin Films b–Ga₂O₃

<p>Fundamental absorption edge of b–Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; thin films, obtained by radio-frequency ion-plasmous sputtering, was investigated, using the method of optical spectroscopy. It was ascertained that the optical band gap Eg increases from 4.60 to 4.65 eV after the heat treatment films in argon atmosphere and to 5.20 eV after the reduction of annealed films in a hydrogen atmosphere. Consolidated effective mass of free charge carriers in b–Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; films after annealing and after reduction in hydrogen was estimated. It was found that the concentration of charge carriers after heat treatment in argon atmosphere is 7.30´10&lt;sup&gt;17&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt; and after reduction in hydrogen, is 2.62´10&lt;sup&gt;19&lt;/sup&gt; cm&lt;sup&gt;–3&lt;/sup&gt; , which is typical for degenerated semiconductors. It was shown that the shift of fundamental absorption edge in thin films b–Ga&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; after reduction in hydrogen is caused by Burstein-Moss effect.</p><p><strong>Keywords</strong>: gallium oxide, thin films, fundamental absorption edge.</p>