Transition between the 1 x 1 and ({radical}3 x 2{radical}3)R30{degree} surface structures of GaN in the vapor-phase environment

Conference · Wed Jan 12 04:00:00 EST 2000

OSTI ID:751874

Munkholm, A; Thompson, C; Stephenson, G B; Eastman, J A; Auciello, O; Fini, P; Speck, J S; DenBaars, S P

Out-of-plane structures of the GaN(0001) surface in the metal-organic chemical vapor deposition (MOCVD) environment have been determined using in situ grazing-incidence X-ray scattering. The authors measured 11{bar 2}{ell} crystal truncation rod intensities at a variety of temperatures and ammonia partial pressures on both sides of the 1 x 1 to ({radical}3 x 2{radical}3)R30{degree} surface phase transition. The out-of-plane structure of the ({radical}3 x 2{radical}3)R30{degree} phase appears to be nearly independent of temperature below the transition, while the structure of the 1 x 1 phase changes increase rapidly as the phase transition is approached from above. A model for the structure of the 1 x 1 phase with a partially-occupied top Ga layer agrees well with the data. The observed temperature dependence is consistent with a simple model of the equilibrium between the vapor phase and the surface coverage of Ga and N. In addition, the authors present results on the kinetics of reconstruction domain coarsening following a quench into the ({radical}3 x 2{radical}3)R30{degree} phase field.

• Research Organization: Argonne National Laboratory, Argonne, IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 751874
• Report Number(s): ANL/CHM/CP-100849
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
CHEMICAL VAPOR DEPOSITION
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
GALLIUM NITRIDES
LASER MATERIALS
PHASE DIAGRAMS