(Color online) RHEED patterns of substrate (a) and homoepitaxial films, thick, grown at 650, 780, and [(b)–(d)]. The images were taken along the  azimuth with electrons. The incidence angle was 1.1° (in-phase condition). The measurement temperatures were the same as the growth temperatures. The intensity of specular spot outside the Laue circle, indicated by the square in (a), was monitored to record RHEED intensity oscillations shown in Fig. 2.
(Color online) RHEED intensity oscillations during homoepitaxial growth at various temperatures in an oxygen partial pressure . Arrows indicate the position of the loss of half the initial oscillation amplitude.
(Color online) x-ray diffraction patterns (dots) and simulation curves (solid lines) near the (002) Bragg condition for three films grown in (650 and ) and .
(Color online) homoepitaxial growth phase diagram as a function of and growth temperature . Contour lines denote the number of unit cells for which half the RHEED oscillation amplitude is lost. The thick dashed line indicates the boundary between two-dimensional layer-by-layer growth and three-dimensional island growth modes. Thick crosses depict a range of the optimal conditions for RHEED persistence at and .
(Color online) Contour map of the increase in unit cell volume, arising from increase in the film axis as a function of and . Thick crosses depict the optimal conditions for RHEED persistence at and .
(Color online) Variation of the room temperature free carrier density with at and . With decreasing , suddenly drops and extrapolates to the carrier densities corresponding to thermodynamic equilibrium oxygen vacancies, indicated for and . This point (marked by vertical lines) also corresponds to the optimal conditions for RHEED persistence (Fig. 4).
(Color online) (a) Temperature dependent resistivity for films with varying , following Fig. 6. (b) corresponding to the films in panel (a). Different symbols for each trace indicate correspondence to the data shown in Figs. 6 and 8.
(Color online) Temperature dependence of the Hall mobility for metallic films. The dashed line gives the best power law fit between 100 and . The symbols correspond to those in Fig. 7. Inset: Low temperature Hall mobility as a function of carrier density for the thin films of this study and bulk single crystals (taken from Refs. 3–6 and 24).
(Color online) Carrier activation energy as a function of for thin films and bulk single crystals (taken from Refs. 5 and 6). The temperature dependent boundaries for the metal-insulator transition for thin films and bulk crystals are indicated by light and dark gray, respectively.
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