Published in Appl. Phys. Lett. 75, 808 (1999).

Inversion of wurtzite GaN(0001) by exposure to magnesium

V. Ramachandran and R. M. Feenstra
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
W. L. Sarney and L. Salamanca-Riba
Materials and Nuclear Engineering Department, University of Maryland, College Park, MD 20742-2115
J. E. Northrup and L. T. Romano
Xerox Palo Alto Research Center, 3333 Coyote Hill Road, Palo Alto, California 94304
D. W. Greve
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213


Magnesium incorporation during the molecular beam epitaxy growth of wurtzite GaN is found to invert the Ga-polar (0001) face to the N-polar face. The polarity is identified based on the two different sets of reconstructions seen on the film prior to and after about 1 monolayer Mg exposure. The inversion boundary is seen to lie on the (0001) plane from transmission electron microscopy images, and a structural model is presented for the inversion. On the Ga-polar face, Mg is also seen to stabilize growth in the N-rich regime.

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