Epitaxial twinned single‐crystal films of copper have been grown on sapphire substrates by high vacuum evaporation in the temperature range 240–‐375°C. The presence of a twin relationship in copper deposited on the basal plane of sapphire was demonstrated and evaluated by x‐ray diffraction techniques. The epitaxy has been shown to be (111)Cu∥ (0001)&agr;−Al2O3; [21¯1¯)Cu∥ [21¯1¯0]&agr;−Al2O3. The films have been found to exhibit the bulk metal resistivity.