Defects in (111) HgTe grown by molecular beam epitaxy

Room-temperature Hall mobilities of (100) HgTe films grown by molecular beam epitaxy can reach values of 27 000–31 000 cm2 V−1 s−1, while the mobilities of (111) films are only 14 000–16 000 cm2 V−1 s−1. We show that the defects which lead to the lower mobilities of (111) films are present in the first 1000 Å of growth. Transmission electron microscope studies reveal a cellular structure of high-angle grain boundaries with some twinning about the (111) growth axis. These defects, and hence the reduced mobilities of the films, appear to result from island nucleation of the films.