Reflection high-energy electron diffraction intensity oscillations during growth of GaN(0001)A by plasma-assisted molecular beam epitaxy

Observation of “Ghost” Islands and Surfactant Effect of Surface Gallium Atoms during GaN Growth by Molecular Beam Epitaxy

“…The buffer layer grown under such conditions has atomically flat surfaces with relatively large terraces. The film has the Ga polarity as judged by surface reconstruction observations [12,13]. The buffer layer growth is interrupted by closing the source shutters, and the substrate temperature is lowered to ϳ400 500 ± C, conditions which promote 2D island nucleation [12] due to reduced diffusion length of adatoms on the surface.…”

“…The film has the Ga polarity as judged by surface reconstruction observations [12,13]. The buffer layer growth is interrupted by closing the source shutters, and the substrate temperature is lowered to ϳ400 500 ± C, conditions which promote 2D island nucleation [12] due to reduced diffusion length of adatoms on the surface. GaN growth is reinitiated at the low temperatures for a specified period before the sample is thermally quenched and transferred to the STM chamber for analysis.…”

“…Figure 3 shows a series of STM images of surfaces following various Ga depositions but at the same N exposure. To achieve this, we first prepare GaN buffer films (at 650 ± C) under the stoichiometric condition [12], followed by deposition of different amounts of Ga from the Knudsen cell at low sample temperatures ͑400 500 ± C͒. The surfaces are then exposed to a fixed amount (0.25 ML) of N before thermal quenching for STM analysis.…”

Growth of GaN on Si(111): Surfaces and crystallinity of the epifilms and the transport behavior of GaN/Si heterojunctions

“…In this investigation, the deposition rate of the film was maintained the same, which was $0.05 BLs=s, as determined by either N or Ga flux in the Ga-or N-stable regimes, respectively. 28 The growing surfaces were monitored in real time by the RHEED operating at 10 keV, where the diffraction patterns were captured by a charge-coupled device camera or a commercial digital camera mounted on the phosphors screen. Both pand n-type Si(111) substrates were adopted for GaN epitaxy.…”

“…In this set of samples, the flux ratio between Ga and N has been kept at 0.88:1, so the growth was in the so-called N-stable regime. 28 Growth at higher temperatures, e.g., 800 C, were also attempted, but the RHEED shows no GaN nucleation but a dominant nitridation process of Si as characterized by the appearance of a (8 Â 8) pattern. 29 At temperatures below 650 C, we observe the surfaces quickly become amorphouslike upon the initiation of GaN deposition as characterized by diffusive RHEED patterns shown in Fig.…”