Effect of ytterbium oxide co-doping impurity on the structure and transport characteristics of (ZrO&lt;sub&gt;2&lt;/sub&gt;)&lt;sub&gt;0.91-x&lt;/sub&gt;(Sc&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;0.09&lt;/sub&gt;(Yb&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;x&lt;/sub&gt; (x = 0 - 0.02) single crystals