Dependence of charging on crystallographic orientations of an as-grown α-quartz

The scanning electron microscope copper-detector technique introduced most recently by H. Gong and C. K. Ong [J. Appl. Phys. 75, 449 (1994)] is employed for the investigation of charging on faces m {101̄0}, R {101̄1}, and χ {516̄1} of single-crystalline α-quartz. It is found that the charging ability decreases in the order of m, R, and χ, revealing the dependence of charging on crystallographic orientations, and these results are confirmed by the well-established mirror-image method. In addition, the experimental results also suggest that not only electron-irradiation-induced defects but also intrinsic defects are responsible for charge trapping.