Investigation of the initial chemisorption and reaction of fluorine (XeF2) with the GaN(0001)-(1x1) surface

X-ray and ultraviolet photoemission and X-ray-excited Auger spectroscopies have been used to study the initial chemisorption and reaction of fluorine (XeF2) with GaN(0001)-(1 X 1) surfaces. An inhomogeneous layer is formed, with a saturation coverage of Theta(F)(sat) approximate to 0.67 monolayers, which is stable up to similar to 550 degrees C. Higher coverages are attained under similar conditions on surfaces damaged by N-ion bombardment. Band bending on the ordered surface is essentially eliminated by chemisorbed F. Ga atoms bonded to two or three F atoms are identified in the fluorinated layer through the appearance of a chemically-shifted satellite in the Ga 3d XPS and of other features associated with GaF3. However, the additional presence of a 'GaF-like' monofluoride and/or N-F bonds cannot be excluded. (C) 1997 Elsevier Science B.V.