Figure 28: TEM bright field (11.0) cross sections of homoepitaxial undoped ZnO film E1289 taken with two different g-vectors (left), taken by Wagner (see [54]). The few dislocations for 𝑔 -vector in c-direction are out of contrast for 𝑔 = [ 1 1 . 0 ] , therefore their Burgers vectors are of c-type. The film thickness is 8 9 3 ± 5  nm, as determined from the intensity oscillations in the HR-XRD 2Θ−ω scan (not shown here). The right inset (provided by W. Mader, Bonn) shows for comparison a heteroepitaxial PLD ZnO film on c-plane sapphire E435 with much higher dislocation density, in particular near the interface.