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Abstract
Single crystal metal films on insulating substrates are attractive for microelectronics
and other applications, but they are difficult to achieve on macroscopic length scales.
The conventional approach to obtaining such films is epitaxial growth at high temperature
using slow deposition in ultrahigh vacuum conditions. Here we describe a different
approach: sputter deposition at modest temperatures followed by annealing to induce
secondary grain growth. We show that polycrystalline as-deposited Cu on \alpha-Al2O3(0001)
can be transformed into Cu(111) with centimeter-sized grains. Employing optical microscopy,
x-ray diffraction, and electron backscatter diffraction to characterize the films
before and after annealing, we find a particular as-deposited grain structure that
promotes the growth of giant grains upon annealing. To demonstrate one potential application
of such films, we grow graphene by chemical vapor deposition on wafers of annealed
Cu and obtain epitaxial graphene grains of 0.2 mm diameter.